No one centralized database, but there's a Winamp3 plugin that searches multiple databases for lyrics... Unfortunately, none of them have times in them. Adding times would be kinda simple, you'd just need a program which takes the regular lyrics and shows them in a window, and plays the MP3 back for you. Then as each line of the lyrics comes up, you could just click, and it could tag that line with the current time in the song. We could use the Tag Tool from Kuo's Lyrics Displayer as a starting point.

There used to a bunch of little sites with tagged lyrics, but it seems they're all on Geocities and Tripod, and are woefully out of date and don't have any files on them anymore.