I would recommend GIMP - it is better than Photoshop Elements, but not quite as powerful as Photoshop CS3. Happily, it is open source freeware.
To get it, you need to install Apple X11 from your install disks, and then GIMP.
Do this to install Apple X11:
1/ Put in your main install DVD
2/ Double click Optional Installs
3/ Opens a second window showing Optional Installs.mpkg and Xcode Tools
4/ Double Click Optional Installs.mpkg
5/ Runs installer
6/ Agree to everything
7/ Eventually get to "Installation Type" step
8/ You will see a list that starts with Applications
9/ Expand this list
10/ Check X11 (last entry in list)
11/ Go through the installation itself
Now do this to install GIMP:
Go to GIMP Mac web site (
www.wilber-loves-apple.org/pages/download.html)
Install X11 patch (see link on the page - follow it and follow instructions)
Restart as required by the X11 patch installer
Download Gimp
Follow the installer.
Done!
Note that GIMP is fairly well documented. You can go to Amazon.com for example and find books on using it just like you can for Photoshop Elements and Photoshop.
By the way, lest the web site name above be perplexing, the GIMP's icon is a (fox?) named Wilbur, hence the "Wilbur-loves-apple" name.