iWorks is not covered in the OSX Missing Manuals; you'll need a different book for iWorks or detailed iLife. The Missing Manual series is great! I highly suggest the Leopard Missing Manual, even if you wait a little while before getting it. Also, you are probably already aware that Apple's website has great video tutorials on switching and using a Mac for the first time.
Another suggestions is Lynda.com. It's only $25/month. They have excellent videos on using Leopard, Macs, iWorks, iLife, etc. My entire family uses Lynda.