Ehhh... it's not really much like counter-strike at all. About the only thing they have in common is that they're first person shooters and they're round-based. Counter-strike came after paintball, though, so if you see any similarities, you should re-order your phrase.
But thanks. I'm not sure what aspects of counter-strike you want it to be more like, but there are certainly a number of maps available. Nothing that really has the layout of an popular CS maps though.
http://dpball.com/files/maps