Ok, so this isn't a tutorial about making icons, but rather what to do with the ones you didn't make. And it may seem like a "duh" to a lot of you; it did to me too. But I've gotten enough questions about it in the past, and have seen enough people who honestly don't seem to know how to do it that I wrote a tutorial. Perhaps it will be helpful. ;)
The question of exactly how to credit seems to be a pretty common one, so this is a brief tutorial on just that: a keyword credit how-to.