lrc.pl, completely rewritten from last time, supports Rhythmbox and Quodlibet. Quodlibet support requires a patch, against quodlibet-1.0 (on ubuntu it's actually part of the package exfalso, and the file is installed as /usr/share/quodlibet/qltk/dbus_.py. Also doesn't support seeking in Quodlibet.
offset attribute, but I might have offset it the other way, which I found to be more accurate with the pile of LRC files that I have obtained.
As usual, just name the LRC file with a
.lrc appended to the song file name. It detects which supported player you have running, and can reattach to it if you restarted it as well. Reattach to a different player is not currently supported. Players other than Rhythmbox and Quodlibet is also obviously not supported, but shouldn't be too hard if it works with DBus.
Oh, if you are using the QuodLibet patch above, make sure that you are careful with the names. I had to use _ instead of . because Dreamhost's configuration stupidly tries to execute every file with a ".pl" or ".py" even when they are in the middle of the file name. Ugh.