Useful Sticky Notes Program?

[latersville]

I have been searching, without success, to find a sticky notes/post-it notes program that will do what I need it to do.

I create folders for each of my clients, and then save all their related files into them. A typical folder contains .doc, .pdf, .jpg, .txt, etc. files.

What I am looking for is a notes program that allows me to attach a note to any of those files. Here's the tricky part...I would like the attached note to pop up when I mouse-over the file name.

I want to use the notes to give me a more detailed description of the file that is possible than what the file name gives, they could tell me whether I've printed the file, what page it is in the case book...things like that.

I would appreciate any suggestions you have as well as what your experience has been with various note programs.

Thank you very much.