We use Parallax's SX/B compiler for our SX projects -- in fact, the code in the AP-8, DC-16, FC-4, and RC-4 is written in SX/B. I'm working on a book for Parallax and they've posted the first part; some of you may find it helpful.
http://forums.parallax.com/forums/attach.aspx?a=15477
Please understand that this is a draft and there may be small errors. I'm working on the projects chapters now.