Android 1.6 (CM-4.1.999)
Just installed CyanogenMod 4.1.999 and its all working perfect
all the google apps work and it looks like my phone is going faster
you can find the installation manual here:
http://forum.xda-developers.com/showthread.php?t=567610
Or
http://www.simplehelp.net/2009/10/04/how-to-install-cyanogenmod-4-1-99-on-your-g1-android-phone/
