ROMBrowser will eventually be a java based ROM file organizer. If you like to play with emulation and emulators, you know the pain of keeping track of your thousands of ROM files, not to mention figuring out what it is you've just downloaded. That's what ROMBrowser is for. Eventually I hope to have a system that works somewhat like romcenter, but is java based and GPL'd.
I also am planning on developing a schema for storing meta-data related to ROM files. There are currently several databases out there that have information about ROM files, usually keyed by the file's CRC32. Part of the ROMBrowser project will be to develop an open standard for that kind of data (probably an XML DTD) and a plan for the distributed classification of ROM files, so users can classify unknown ROMs and distribute that information.
Here is a link to the first release of ROMBrowser. You will also need rom info databases in order to get your roms categorized, go to the rombrowser project page for information and downloads.
Further down the road is linking the browsing functionality to a launcher, so the system can serve as a front end to MESS, RockNES, etc.