Is there plans for an illustrator forum? If not, you should make some. Illustrator is an important part of CS4 so I think people will want to talk about it.
Now that I am becoming more confident in Photoshop I wonder what the differences are between Photoshop and Illustrator? I'm not an artist by trade, would Illustrator be easy for the uninitiated?
As DJDanny said, the main difference is that Illustrator is a vector based program, which basically means you're not working with pixels like in Photoshop.
It took me a while to get into using Illustrator, but it's a very handy tool. I've found a lot of things that I used to do in Photoshop I now do in Illustrator, and it's a lot easier and more flexible!
One thing I like is that you can have both applications open and just drag things between them, so they work together as a team very well. I pretty much always run them together when I'm working.
If you have Illustrator installed you should open it up and mess around a bit. There's a couple of very good tutorials here for Illustrator if you want to really get into it.