Re: PIC kit 2 C compiler
You have the free (lite) compilers CSS lite and Hitech-C, both can be integrated in MPLAB. They don't have a code size limitation, and for both compilers, you can find a lot of libraries. The only 'limitation' of the free lite version is that it does not perform all possible code optimizations. But in practice, you will hardly be aware of this, unless you are running short in memory.
In that case, you are already writing large programs, and then you can consider using a more powerful 18F instead, which can be compiled with the C18 from microchip (also integrated in MPLAB) which comes standard with the most important libraries.
I don't know tutorials for the CCS or Hitech-C compiler, but for C18, you can find some tutorials e.g. for the USB capable PIC18F4550 **broken link removed**.