I have a T-Mobile G1. That phone is an essential part of chasing for me this year. It does quite a bit and there are a few weather apps in the Market for it. I have quite a few and some are better than others. It is kind of frustrating because some are better than others. Like even with 3G coverage some of the programs run a bit slow as far as radar goes. A lot of them use Google Map based radar/satellite/lightning overlay... I must say I HATE that radar. Probably because it is not too detailed AT ALL. However, it is long range which was helpful when my nearest radar site was down due to a lightning hit.
Anyway, here are the apps I have on my phone:
Aviation Weather from NOAA/NWS which offers Aviation text, radar, satellite etc. It is an experimental app but pretty decent if you need TAF/METAR (translated and raw) and PIREPs
AccuWeather Well, what can I say? It is AccuWeather. The only thing about it I like is the quick loading radar which is not so awesome because you cannot zoom, but it is not bad if you need something instantly.
iMap Weather This program is okay. It is not terrible but I find it can be difficult and slow to work with at times.
The Weather Channel I really like this app. It is somewhat similar to iMap but it offers more features and is more reliable with things like warnings. It has a widget to display current conditions on the desktop of the phone. You can set alerts for warnings and such.
Everyones tastes are different and I suggest just playing around with the different programs. Until we can get GR3 for Android, that is what we have to do.