so i am a noob here but i would like to share this info with all Att users i have HTC Aria running android 2.2 non-rooted and i was downloading launchers from the app market, not sure which one allowed me to get the "UNKNOWN SOURCES" OPTION but I will share that i have downloaded AWD.LAUNCHER along with the GINGERBREAD THEME AWD and at the same time downloaded an app just called LAUNCHER and both had flaws i did not enjoy so when i went to delete them in my Applications menu i now have the option to allow non-market app to be instaled hope this helps ya'll