I will try work for a 'Clockworkmod' after i get my own SGA (Now using my brother one) which will allow you to install custom ROM..
it is an app with a very friendly ui that allows root users to do various things. The first and most important would be flashing a recovery image. With this you are able to create a nandroid backup of your current rom should something you do crashes or bricks your phone. This would be done through the recovery menu, you can get there through clockworkmod or simply power off the phone then press both volume keys while pressing the power button. The other thing it allows is the installation of custom roms, like CM6.x, which is the developers, koush, custom rom.
or maybe Android 2.3 on SGA...

LOL .. ==" i think we need to install 'ubuntu64' before compiling the script ... and i cant do this all alone.. need someone know how to code this language .
Compiling Clockwork Mod From Source :
https://github.com/CyanogenMod/android_bootable_recoveryMisc :
http://www.koushikdutta.com/2010/02/clockw...very-image.htmlhttp://www.koushikdutta.com/2010/03/rom-ma...party-roms.htmlhttp://www.droidforums.net/forum/droid-dev...tml#post1106908UPPDATE : anyone dare to try the ' Rom Manager ' ?
Go To The Market & Install "ROM Manager" Open That App, Select Flash Recovery, Confirm, Then Go To Install From SdCard.
Select The Unrevoked-Forever Zip, (Make Sure It's Put On The Main Directory Of Your SdCard)
Next I Believe It Will Bring You To Your New Recovery Screen!!
*Note* Recovery Menu Can Be Accessed By Powering Off, Then Powering Back On While Holding Volume Down, Once The Phones On Press The Home Button To Get Into Recovery!
hmm.. but there are no custom ROM out there yet.. we need to make it.. or wait for xDA ppl to make it.
(I dont know this will works or not) NOT TESTED on SGA
This post has been edited by xDragonZ: Mar 17 2011, 12:20 AM