Eric Sink has chapter 7 of his Source Control How-to up, and it's about branching. It's not really a how-to in this part, but a why-to and a whynot-to. It's a very good read, as usual, and gives some very practical reasons to branch, and then offers words of caution about branching. Next time, he'll be talking about merging. I'm looking forward to that one.

In the mean time, go read about Nelly and Eddie.