Google is set to launch an app for the G1 that will give users the ability to edit Google Maps right from their phone.!

G1 users will be able to sync from their Android powered phones, to their online Google Maps app, or the other way around. 

So, you can plan your trip on your desktop at home, then sync it to your phone for the trip. 

Or, you can use your G1 on a trip and then sync it to your online Maps, to share with others, or save for future adventures.

Users can also mark key travelling points using handset GPS and attach images taken using the phone's camera.

At first, it will only work with the T-Mobile G1 but that should expand as other Android powered phones hit the market. 

[source]