I found 7 weeks to cycling fitness (put out by DK) a really useful book. Takes you through all the great basic techniques for cornering and coveres differences between roadies, mtn bikes and hybrids. Even things like cleaning and bike maintainence were in there.

But most of the best information I found here on the boards. Read a LOT of different threads on bikes, commuting, maintenence, mountain biking or racing and you'll get an idea of what you may like to use your bike for and therefore which bikes to test ride.

Good luck hope to see you out on a set of perfect for you wheels really soon!