Of course you need a camera.. It's really got to be a Digital SLR, you need to be able to manually focus, set aperature and being able to save to raw really helps.
I'm no expert on SLR's. I use a Canon EOS 450D but pretty much any DSLR will do.
Ok so you have a camera. Next a tripod. Spend a little money on this, try some out in a shop and find one you like. It's REALLY helpful to have a smooth movement and a good locking action so that you can micro-adjust the camera's position and then lock it in place for a whole session. Nothing's worse than taking a whole bunch of shots and then realising you nudged the camera slightly and the best shot of the night is half out of the frame.
Remote release for your camera. Nothing fancy here, most makers sell em for £30-40 but you can pick up an IR trigger off ebay for as little as £1.50
Next time : Lenses and Getting up close!