I can highly recommend all of the books by Jan Somers.
Don't know about ordering online - they are generally available in the bookstores here in Aus ... obviously in the US you will have to hunt around ... Amazon is as good as any I guess.
Remember they were written in the Australian context. I think the basics should be similar but we have a different taxation system here which you need to keep in mind.
I found them very useful and am always lending my set out to people!
Business Mall is an on-line store affiliate of the Australian Property Investor magazine, and has an entire section devoted to them in every issue of API magazine.