I really love my ps3 but the main games i play are first person shooters and the xbox360 controller is perfect for them.My question is,is there a way to use the xbox360 controller with my ps3?

i don't think so, but you can use both controllers on PC however.

i don't think you can use an actual 360 controller but there are some 3rd party clone controllers.

http://www.amazon.com/Shadow-6-Wireless-Controller-Playstation-3/dp/B002ISZB2O/ref=sr_1_15?ie=UTF8&s=videogames&qid=1262302498&sr=8-15

3rd party controller or this: http://uk.gear.ign.com/articles/955/955499p1.html

lulz im loving the 3rd party controllers

yes you can. You need the XCM Cross battle Adapter and a wired 360 controller. I got my adaptor for 20 bucks and the wired controller for $14 so its comparable to price of a dualshock 3. However, these is no sixaxis support so it won't work for some parts of games like killzone 2. 

i dont see how 360 controller is better for fps.

the left right bumper set up on ps3 is far better and more responsive imo. if your talking the left right trigger buttons then yes the ps3 triggers arnt as good for fps, although they are for driving games.

OMG... That controller turned the PS3 pale and made it sick... lol... Yeah, that 3rd party connection is the only way I'm aware of, but, what you could do is go to gamestop, and get some trigger buttons for the R2, and L2 buttons, they snap right over the existing buttons...

Usually, when I play games, I just get accustomed to the controller on that system.. With the exception of the Wii... For Wii, I just use a PS2 controller, but, then the complications come when trying to remember what button on gamecube corresponds to whichever button on the PS2 controller while playing Wii... So, me, not ever actually owning a gamecube, can get pretty confusing... Then, the L1 and R1 buttons have the exact same action, because of the lack of buttons...

It can get confusing, and kinda awkward remembering that X on 360 is SQUARE on PS3..

you might want to attempt this:

http://www.engadget.com/2007/05/01/how-to-make-a-ps360-controller/

will come back to this soon..