Hey Jon! New eventonline right now! You will be able to get Latios, since you play HG.
1. Get your WiFi Enigma stone
2. Go to the museum in Pewter City
3. Find Steven stone.
4. he will have your enigma stone exmined by one of the experts there.
5. you obtain soul dew!
6. Go outside, you'll see a Latios standing on the road!
Since you play HeartGold, you can get Latias without events, but you have to get latios in this event. I play SoulSilver, so I have to do this event to get Latias, but I can get Latios without events... :S