I've been taking climbing photos for about three years. I mostly use an old Minolta 35mm slr with a 35-70 zoom. Occasionally I use one of my medium format cameras to when I want to catch something different and I have been planning to take my 4x5 out and get some good bouldering photos one of these days...
I most recommend having a camera you aren't afraid of dropping (yell "rock!" so you don't pelt anyone with it.. or at least they duck and run ) or more likely than dropping, you bash it against the rock every now and then..
Some guys get pretty fancy with all sorts of gear to hold themselves out from the rock etc... I'd be more inclined to have a wide angle lens for the times you are hanging from the same anchor, a good tele and a medium zoom. From that point on it's about doing the work. Sniping shots usually isn't that effective... A friend of mine who has had several covers on Rock and Ice, etc pretty much sets the entire day for a shoot.. picks the wardrobe, the climb, etc.. 6 rolls of film minimum..
But most of all, have fun climbing. If you can capture the moment then you are doing well.