The C Programming Language Amazon BN
"K&R", the classic C book. It's a little dated, but it's a great read to get the flavor of the originators of the language.C: A Reference Manual Amazon BN
A comprehensive reference for the various dialects of the C language (K&R C, ANSI C, C99, etc). It's got some typos and some problems with the index, but it has a lot of good information.
Code Samples for Chapter 2 (C Refresher, part 1)
Includes bitmask.c, conditional.c, constants.c, factorial.c, file-1.c, file-1.h, file-2.c, file-2.h, first.c, leaveout.c, limits.c, macros.c, variables.c
The comp.lang.c FAQ
Tons and tons of information about C and C's dark corners.An on-line introduction to C programming.