Question about Photoshop, Image Ready, and Illustrator

I didn't notice this in the memories, so forgive me if it sounds terribly newbie-ish.

I've been making my icons with MS PhotoDraw V2, and while it's not able to do a whole lot, I've been pretty happy with what I can do.

Yesterday, though, I got the disks for Adobe Photoshop 7.0, Adobe Image Ready 7.0, Adobe Illustrator 10, and Dream Weaver. Now, I realize that Dream Weaver is for creating flash and desiging webpages, and a whole host of other things that I've only just started looking at, but I'm confused about the differences between Photoshop, Illustrator and Image Ready. So far, they each look like the same darn thing.

Icon wise, are the programs basically the same, as far as capabilities, or does each one have something special it does?

If, and when, I get ready to start adding to the programs and start experimenting with icons through these programs, are the PS7 downloads loadable to all three, or will I have to work around it?

Thanks in advance.