Can i use my gta4 for 2 users in ps3.?

May be...

i have a ps3 which got 2 users on it , one is mine and the other is my brother's. and we have gta4 can i use the game in my user without deleting the achievements in my brother's one. so basically can we use gta4 in bothe users with out deleting the data of one another.

please help

yes

yep of course you can =]