One: Please don't use my icons on websites outside of LJ--journal site or otherwise. It's really just easier to give due credit that way. I don't mind if you use them as icons in instant messengers, but I would prefer for them not to be used on other websites. Of course, all icons are for personal use only. That's a given, especially since my icons are mostly of copyrighted material.
Two: Commenting and crediting is great but not necessary. If you want to credit, you can put this in the icon comment:
by <lj user="iconjuror">
Three: Please do not modify icons if you use them. I'm not a follower of the belief that textless icons are bases--sometimes icons don't need words. :]
That's all, thank you very much!