[lsc]

personally, I'd recommend the classics.

1. winning friends and influencing people by Dale Carnegie

probably the best "quick introduction to people skills" I've seen.

then, if you need to deal with vendor salespeople

2. winning through intimidation by Robert J. Ringer.

(not that I really advocate doing what he says, but it's an important window into the sales mind. You need some applied cynicism to defend yourself the first time you go to rent an office, a server, or anything else, really.)

but, I guess that's only two, and neither is as specific as you want. I've never read a specific business book that I found useful.