Moving the file name(s) into meta data

I have many thousands of JPEG files that have unique file names ( I.e. Scanned doc 1, scanned doc 2 etc. - I am sure you get the idea) I have created an cross reference between the file and the negative. I want to move the file name into metadata in bulk to secure this information even if I then change the file name to something else. I use PS CS3 but can't see how to do this. Anybody know how? Thanks in advance.