Unfortunately this may not be a good move.
Photoshop 6 is very old (anything more than 3 years in the digital world is
very old). You probably can go to Amazon and search for books available for
it. They probably will be "used book" and not expensive. Probably you can
search the web for tutorials for it and still find some existing ones.
If you are serious about getting into this I would recommend a different
route, because the tools available now and how the new software behaves are
so different than the 6 version.
I can understand why you purchased the 6 version, obviously cost. But
spending your time learning 6 is also a cost.
However I think you would do better using Photoshop Elements and the latest
version is 5. You can get this for about $79.00 if you shop around (the
usual rebates) and check the Adobe site to see what they offer and you can
use a trial version from there.
For Elements 5 you will find plenty of books, tutorials on the internet,
Elements 5 forum etc. etc. and it is a much better starting point than
Photoshop 6 and Elements 5 will keep you busy for a long time before you
grow out of it.
