I've read that book. Larry Ullman is a good writer. You should check out his website and look into his newsletter. (Which reminds me I haven't gotten it for a while. Gotta check on that.)
This is a great way to learn! You can also set up a localhost server and try it out that way. I do a lot of my development in localhost before going live with it.
AFAIK, the earliest version of PHP that DreamHost currently offers is 5.3. I'm not sure what is at 4.0 right now.