A friend has some great wheels to sell me, but they're campy and I need shimano. To make the change, all I need to do is change the cassette, right?
Probably not~ What kind of wheels are they? How many cogs are on the back now? Some wheel sets will allow you to swapout the cassette hub body. You might want to go to the Sheldon Brown website on cassettes. Just google the words.
Options ($$$ - $):
1) Change out the hub to a Shimano compatible one
2) Get an American Classic conversion cassette which is Shimano spacing with a Campy spline fit.
3) If it's 10 speed you most likely could get away with running a Campy cassette w/ Shimano shifters.