Steve has managed to port Counterstrike on the iPod Touch using iPhonedoom. It is a bit buggy, the controls could be better and you can play only with bots and not online. We hope the next version makes for all the shortcomings.
You must install it first to do this!!!--->I´ve made my own repo:http://steveboy12.googlepages.com/Repo.xml
It´s a little buggy, but it works fine for me. Let´s start with the tutorial=)
1.You must go into your iPod using SSH. Locate into the folder:
/private/var/root/Media/Doom
If you haven´t the folders just create them!
2.Then you gonna need to download this
--->http://rapidshare.com/files/10151421...AME_FILES_.zip
3.When you´ve done downloading, extract the two files to your desktop.
4.Now you need to copy both files in the Doom folder from step one. When it´s asking to
owerwrite, just click yes.
5.Okay, next you need to set all permissions to 755, that means the doom.app folder under
/Applications/Doom.app and all data in it. Then you do the same with the Doom folder
under /private/var/root/Media/Doom. Of course the two files in it, too.
6.Then you´re done. Hopefully that works for you! I did not used illegal files!!!!!

Via - iPodTouchfans