http://www.oreilly.com/catalog/pcp3/

It's one of O'Reilly's older titles, but still one of the best in print. I used this book to train a group of beginning programmers in C programming on UNIX boxes (in that case, using gcc on Solaris). While the seminal K&R book (http://cm.bell-labs.com/cm/cs/cbook/) is fantastic, it can be a bit "dense" for beginners.

At some point, I would also like to see how well the Stevens books translate to OS X.

Of course, I haven't touched C on a full time basis in five years... yipes.