How to RNG in the 5th Gen:
Well alrighty, first thing's first. Download RNG Reporter, Zomg Timer, and know what your DS Mac Address is. Those are the basic requirements. If you have an AR it makes things a lot easier when RNG-ing.
This is will take a while, but what you want to do first is open up RNG reporter, click Time Finder. Enter in the date, year, and your Mac Address. Select C-Gear as opposed to Non C-Gear in the little box. In the Maximum Frame box, enter 30. In the Minimum Delay box, enter 1000, and in the Maximum Delay box enter 10,000. Make sure and pick which version of the game you have, and then enter in what kind of IV's you would like. It takes a long time searching, so that's why you should do this first. Then when you get the results of whatever spread you picked, or others that could come in handy later, copy or write them all down with the necessary info, (like the Seed and Frame).
So say you found an IV spread that you like. Right click it and select "copy to clipboard". Exit Time Finder and open up Seed to Time. Paste the seed into the box at the top, make sure you select Method 5 C-Gear, enter 50 seconds into the seconds box at the very top, and click generate. This gives you a list of target times and the delay. If the delay is 6000+ it's going to be a little difficult to hit for the first time. A good range is 1800 to 3 or even 4000. So select any time from that box. Then towards the bottom you'll want to enter +999 and -999 delay into the delay boxes, and +9 and -9 into the boxes next to those. This will show you if you messed up, and gives you a big range in case you did. Then click generate. This will show adjacent seeds and their delays.
In Zomg timer, enter the target delay that you found in Seed to Time, and enter 15 into the seconds, and 49 into the target seconds. (I know I said 50 earlier, but I know with mine I would always hit 00.00.51 instead of 00.00.50.) You can kind of mess with it in case that doesn't work. For the Calibrated Delay, enter 805, I'll explain the details later.
Alrighty, now to know terms and stuff. :) I know all that probably sounded confusing, but it's good to get that part out of the way ^^'
So say you want to catch a Pidove with 31/31/31/31/31/31. Your target time is 3:45:50, date 1/3/2011, delay 2322, frame 7. (Just a random example)
The target time is the time you want to hit "yes" when it asks you to turn on the C-Gear in the game. So when you are starting up your game, make sure and hit NO when it asks you to turn the C-Gear on, and yes to the other prompt. Then when the game is starting up, click the power button on the c-gear and wait for the timer to reach zero before you press "yes". So basically, the target time is the time you want to start your game at, by hitting yes on the c-gear prompt, in game. This is where Zomg timer will help.
There are two timers with RNG-ing. You activate the first timer at the exact same time you change the clock on your DS. So you would change the time to 3:44 (one minute earlier, or whatever Zomg timer says) and hit start on the timer and yes on your DS screen at the same time. Then turn the DS off, insert the game (with or without the AR) and wait at the screen where it says to choose the game. Right when the first timer goes off, hit A. Then this is the difficult part believe it or not... press A at a steady, comfortable pace, through the intro, and through continue on the game menu. Keeping a consistent tapping of A is important to hitting the delay, not necessarily the time. Your timer probably won't be up yet, so just wait at the screen where it asks you to turn on the C-Gear while you are already in the game.
Ok, so lets say you've done that. You started the game and you are pretty confident you hit the right time. Before you move or do anything, have a Pokemon with sweet scent, use it, and find a wild Pokemon. (I recommend going to victory road so you can verify its IV's easier). Catch the pokemon, check its IV's through Metalkid IV calculator, or with an AR.
Have RNG reporter already open, with the Seed to Time window open. In the "Enter IV's" button, enter the Pokemon's IV's you just caught. It should hopefully show you that you hit your time... but, say you missed the delay. It will show you the delay you actually hit. Enter that delay into the box under "Frequency" on Zomg timer and click update. This will change your Calibrated Delay, as well as change the time on the timer. It is very important to calibrate at first, so re-do the whole thing, making sure to tap A through the game intro just like you did earlier.
So say you hit 2322, the Target Delay. Since you've already caught and verified the Pokemon's IV's, you can't go catch whatever Pokemon you wanted with those IV's, since battling a wild Pokemon will advance the frame by 120 per second (but can be very useful when hitting VERY high delays ^^'). But knowing you hit your delay is very important! That means whatever it says in the Calibrated Delay, is a common number to put in that box whenever you are going to breed/catch something. So say the calibrated delay is 811. Enter that in every time, and skip the calibrating part. Just make sure your tapping of A is pretty consistent.
Ok, so if you've got the calibrating down, now it's time to advance the frame. The target frame is 7. The starting frame for wild captures is 3, and the initial frame for standing legendaries and wild captures is 1. So the equation is target - starting - initial + 1 = How many advances needed to reach the target frame. So 7 - 3 - 1 + 1 = 4. Well ok, so how do you advance the frame? Pretty easy, even though it doesn't seem like it is. For every 128 steps you walk, it will advance the frame by how many Pokemon you have in your party. So in this situation, for example, you would have 2 Pokemon in your party. Walking 128 steps, 2 times, will advance the frame by 4 times, which will bring you to your target frame of 7. An easy way to track this would be to add 128 + 128 = 256 and use 1 Max Repel to track your steps, then walk 6 steps. After that, use sweet scent and check the caught Pokemon's IV's. If the IV's aren't what you hoped, don't give up just yet. Close the Seed to Time box in RNG Reporter. Enter in your seed in the Seed box, select Method 5, and enter the IV's you got instead (make sure and say they are equal to those IV's). Since you spent a while calibrating, you should be able to change the last letter or number of the seed to 1-9 or A-F. Try doing that and see if you got one of those seeds, then plug that seed into the Seed to Time box, and enter that delay into Zomg Timer.
It is a lot of trial and error, but once you finally get it, then it was all worth it. :)