The main site is a blog called Mac Kindergarten and there are a lot of great tips there.
An article that tells you basically what Pages in iWork is and is not can be found on Obvious Diversion and it might be a good idea to read this before you dive in and play with the program. A comment that I would add is that while the article talks about Pages just as a word processor it functions very similar to Microsoft Publisher in that you open a template and you can keep it exactly the same and just replace placeholder text with your content or you can move everything around, completely remove some parts and pretty much re-invent the pretty wheel to suit your own needs.
TeacherTube video tutorial for KeyNote
There are quite a few video tutorials on TeacherTube for Macs. I recommend going to the searchbox on the website and just search for a program you want to learn about. This is a great way to get introduced to the software before you dive in and play.