Why wont itunes 6 remember changes made to songs???

Hey guys, does any1 know why itunes 6 wont save/remember the changes i make to a song? For example, if i change the album name from 'blah Blah1007' to 'Blah2007', when i click on the song again later, itunes will display the album name as the unchanged one. i.e. 'blah Blah1007'. This is so irritating as i have so many files. is there anyway of making itunes stop doing this?

ANy help is appreciated. Thanks!