HTC desire with CM7/CM9

http://wiki.cyanogenmod.com/wiki/HTC_Desire_(GSM):_Full_Update_Guide

1. Use revolutionary to S-OFF and flash ClockworkMod Recovery
(Or power+voldown)

2. Use CM Recovery( to flash radio, CM7, google apps...
    (You may need to use fastboot to flash radio..., need to download HTC driver and use AdbWinApi in revolutionary...)

3. Boot into CM7, use ROM manager to upgrade to ICS (download ROM->Desire ISC ROM)