Icon Manager is an excellent app for creating and editing icons on your Palm. With this application you can also create your own customized icon file that only has the icons you use.

Maceyr has an excellent Icon Manager blog post with links to many free icon sets near the bottom.

Update 2009-10-11: Fixed links

Leslie Franke's blog has an entry listing what he considers to be the best free Palm software. I agree with many of his choices and was grateful to learn about Icon Manager.

Just learned of MSMount5 from Notes on Going Retro with a Clié N610C.

I've only spent a little amount of time playing with it, but it appears to allow you to access applications and databases that exist on the SD card. I have confirmed that an application copied to the /Palm/Programs/MSMount directory on my SD card shows up in the default launcher without needing to select the card first. Cool!