From the README.txt
RF-mod 1.0
Features:
Song Folders in play menu and editor menus
Song Timer during song play
More information in song results
Toggle for alternate key settings in game settings menu (you can swap easily between keyboard and GH controls)
Toggle for disabling animated flames in video menu (can reduce CPU usage)
Toggle for disabling preview songs in audio menu (reduces cpu/memory in song selection)
Memory cleanup (less memory leaks)
In order to install this mod you will need to
1) Be running Frets on Fire 1.1.324 on Windows (no linux version yet)
2) Back up the 'library.zip' file you find in the 'data' subdirectory
3) Replace the 'library.zip' file with the one included here.
4) Copy the 'folder.dae' file into the 'data' subdirectory
Here's a pretty picture of the folders:

You can download the current version of the mod:
From here
And remember to read the README.txt
Please any replies, comments or questions on this thread. I will be duplicating this information in the completed mods thread for reference.
I would like to thank FoZZ for creating the folder guitar case. It looks really nice. Label support for this coming soon. It would have been in this version but FoZZ's machine seem to have died so it will take him a while to recover.
New features coming soon hopefully. Also the source diffs are included and I will be submitting them to the authors to see if some of these can be rolled into the next version.
-Alex