This article is from the alt.comp.lang.learn.c-c++ Frequently Asked Questions. Compiled by Sunil Rao email@example.com.
The best online tutorial for C I have come across has got to be Steve Summit's class notes for the C courses he teaches. http://www.eskimo.com/~scs/cclass/cclass.html
There are references to other C tutorials in his C FAQ as well.
Vinit Carpenter maintains a list of resources for learning C and C++. Do note, however, that a fair number of the tutorials placed online contain mistakes and/or are out of date. http://www.cyberdiem.com/vin/learn.html
Ted Jensen's tutorial on pointers and arrays in C can be found at http://pweb.netcom.com/~tjensen/ptr/cpoint.htm
Tom Torfs has written an excellent, complete tutorial, meant to complement a good introduction to C. It's not primarily intended for the complete beginner to the language, though. http://members.xoom.com/tomtorfs/cintro.html
See also the answer to question 18.