I imported a cd with 35 songs into iTunes, then pasted all the Titles and Artist Info in caps, instead of making the changes in iTunes I used MP3Tag to make the changes under "Case Coversion" and it was all done quickly.
I also had to Covert Tag to Filename because the file names was track 1, 2, 3 and so on, which worked perfectly.
The problem I am getting now is that iTunes can't find the files anymore and I have to Locate them all individually one by one to re-link them, doesn't the MP3Tag changes suppose to transmit back to iTunes, that's how they use to work?
re-linking will be a bit tricky as iTunes relies on the filename - I am afraid that you will have to do it manually or use a tool like itlu (itunes library updater) - which only works reliably under XP. This tool would delete missing tracks and import new ones. Your original playlists would be spoiled, though.
BUT: if you leave the filename as it is when you originally scanned the file for iTunes then iTunes will update the tag information the next time it touches the file.
Metaphorically speaking: filenames are void and say nothing about the contents. The information is stored inside the file in the tags. Any kind of (better) player does not care what the filename is - the filename is only for the housekeeping tasks of the underlying operating system.
So if you want to get a meaningful filename it might be a good idea to tag and (re-)name files first and then import them into iTunes.