Comparison tool

Fairly simply request:

Has anyone found a useful tool that can compare 2 given files and point out all differences (i.e. output in a new text file with "line at which difference encountered", "file X has Y vs file A has B")?

If not, would someone be bothered to wirte one? :)

I would hate to have to abuse the wikipedia sandbox with M2TW files to figure differences ;)

I use UltraCompare. It isn't free though (comes with UltraEdit)

I use Compare It. It is free.

http://www.download.com/3000-2248-10048256.html

Thanks :)

I use beyond compare 2, not free but try the demo and see what you think.