I would start by typing "art messengers" without the quotes into iTune's search box in the top right corner of the window. That should list all tracks with the tags you mentioned.

You can select all those tracks and when editing tags you will automatically be working on them in batch.

Renaming the files is where it gets tricky if you're using Windows. On the Mac you can get a number of AppleScripts as well as iTunify which provides a nice GUI for a lot of the same features as many scripts plus a of of RegEx support. You would need something similar to plug into iTunes to handle the renaming. Or use a more conventional tagging program such as MP3Tag, Tag&Rename or Dr.Tag.