well they averaged out to about 98db so set them all at that.. it was only a max of 3db different for each one so should not affect quality too much TBH!
Beatjunkie... the programme is MP3gain and its free:
http://mp3gain.sourceforge.net/
'MP3Gain does not just do peak normalization, as many normalizers do. Instead, it does some statistical analysis to determine how loud the file actually sounds to the human ear.
Also, the changes MP3Gain makes are completely lossless. There is no quality lost in the change because the program adjusts the mp3 file directly, without decoding and re-encoding'