Hi Peggy
Best book I found, fortunately reaosnably early on, was The Backyard Astronomers Guide.
http://www.amazon.com/Backyard-Astro.../dp/1554073448
The writers seem very experienced in imaging with DSLR and they have some good advice on equipment etc discussing pro's and cons.
Its a good read, as are all the other recommendations here and of course theres a lot of info on teh various forums. Sometimes though its nice to just go through something in a logical sequence and thats where I found this book most useful
Good luck, and oh yes, dont skimp on your mount. Doesnt matter what sort of camera you get if your mount cant cut it
