The Foam Book also teaches you the basics without having a pre-designed pattern. In fact, a lot of the book is about you creating your own pattern and how to get shapes out of foam.

Yeah the Foam Book is great. That was one of my first aquisitions. I really want to be able to consistently produce the same character(s) and so a pattern is really the way to go. I know I could always create a puppet and then dissect it to make a pattern, but it's hard to bring myself to uncreate what I just created.

Jeff,
I know it can be hard to disassemble something but that may be the best way to get your pattern.   I normally try to pattern as I go but often I end up altering the final foam or fabric itself to get what I want. I try to translate those changes to the pattern I made but that does not always work out.

What I sometimes do is make the pattern as I go. Taking measurements where necessary or creating a paper pattern after the fact. That way I'm not going to need to dissect anything afterwards, and I still have something I can build from later. This is how I work with a lot of my tutorials on my site, because a lot of the time I don't exactly know what I'm making and how, and even more so, a lot of the time I need to go back and fix something so the instructions/results are better. Sometimes it's just a matter of remembering what I did, and not so much making a pattern; I always have a notepad so I can write down any instructions that would help me in the future.