I agree there are TONS of things on the net,,
www.cleanrun.com has alot of info, and a "store" where you can find some really good books.
And I agree with the above poster, if your interested in competing, find trainers who have been there and done it successfully.
I started in agility about 8 years ago with my GSD, she was an easy training driven dog who loved ripping up courses. I have had some wonderful trainers, but it also helped that my dog was such an easy trainer. She's retired now, after ranking #4 GSD in the US, in 99 & 00..Now I run an aussie who doesn't take life as seriously as the GSD did *vbg*.
ANyhow, just do a search on "dog agility", and you'll find tons of reading
The Clean Run site also has a section listing dog training facilities and trainers by area so you should check that out as well.
Good luck, it's fun and addicting.
diane