sorry to post back to back, but I didn't want an extremely long post. As a result, I posted some of the potential problems I see in a seperate post:
Problem #1: building the database
We could have the program analyze the mp3 libraries of users, strip the information from them, and add it to a central db. The central db could be placed online and updated daily by users at the click of a button.
If the abum is not found, the program displays a customizable message, nothing at all, or an info not found message.
Problem #2: analyzing the song
I am not sure how long you would have to analyze to get a fairly unique representation. Most songs are unique for the first 10 seconds, but 30 seconds or so may be necessary. Even so, I would love to have that info displayed for the song length - 30 seconds.