One of the issues of Apple's Develop magazine a long time ago explained the Boyer-Moore, the Tuned Boyer-Moore, and the Self-Tuning Boyer-Moore, which is what I used for a C library I was working on at the time.

If you think Boyer-Moore is a trip, check out Self-Tuning Boyer-Moore. There's actually a really good writeup on it at http://www.grouse.com.au/ggrep/string.html