When starting, I found lots of helpful resources by browsing crochet books at Barnes-Noble, then checking out the ones I felt looked most helpful from the library. And many of these, I wound up buying for my personal library of resource books. User comments for various crochet books listed on Amazon, were a helpful guide to finding the most helpful resources.
One book that was especially helpful at the start, is Stitch 'N Bitch Crochet...The Happy Hooker by Debbie Stoller. After checking this out of the library a couple of times, I eventually bought my own copy.
And, as already mentioned, YouTube is a great learning resource.