there aren't any books on C for the PIC. not that I know of at least. As far as I know, the only language you're likely to find many books on specific to PIC programming is assembly, since that's the standard.
and no, I do not mean C++. C on the PIC is the same as any other form of C except for the stuff specific to the PIC... like the variables corresponding to the settings registers, and the PORT and TRIS registers... the stuff you have to deal with in any language.
your best bet is to search the net for examples. you'd probably be best getting a basic understanding of C before you try to do stuff on the PIC specifically.
check out sparkfun.com. they have a ton of info. from what compiler to use, what editor to use, how to compile, how to program, etc... as well as example programs.