How to be a gardener...from the BBC
This great, interactive site has some wonderful information on gardening and how to do it. Although the site is focused on the UK, there is a lot of information here for any gardener.
From the web site...
"This online resource, prepared in collaboration with the Royal Horticultural Society, will bring life to your learning. There will be eight modules in all. You can work through them, or simply dip in, it’s up to you. The modules cover everything you need to know to give you a great start in gardening."