Grab the BoostC demo from
SourceBoost. It's an excellent PIC compiler. The demo works on all supported PICs. It's only memory and code size limited. When your programs get too big for the demo you can buy a full license for about $75. That gets you both 16F and 18F compilers, as well as support for some 12F's. A ton of bang for the buck!
You can't beat that deal anywhere. Microchip's C18 is about $500 and is for 18F's only. You get to pay again to get another compiler for 16F's. PICC is around $1000 for a full license, I think for only one family (16F or 18F). I could be mistaken about that, but still it's a lot of bucks if you're a hobbiest.