In terms of learning C, I'd say to use something like
-> K & R <-- C bible (Although kind of outdated, 2nd edition is Ansi C)
-> C Programming: A modern Approach (the "heir" to K & R as said by some)
If you want to make it fun, you can learn C along with
-> Hacking The Art Of Exploitation (It teaches C as well as how to debug/dissassemble which is pretty cool)
-> Advanced Programming in the Unix Environment (Teaches more about the Unix system along with C)
All these books can be torrented and found online, have fun : )