I tried to use Pandora's Jar with Ubuntu Edgy and FF2.0 and had no success. That, however, inspired me to try to come up with my own method. I submit the bash script below in the hopes that it serves as a help to the developers of Pandora's Jar for a simpler way to time-shift songs.
Modus Operandi: Anything other than Ubuntu Edgy and Firefox 2.0 is a complete unknown, so don't expect it to work. But if you have those two, keep going. First clear your cache. This step is fairly important, especially if you've been using Pandora earlier.
Then in a terminal start the script with "bash ./pand_ts"
It should output only the text "Making all temp directories."
Next load Firefox and go to Pandora.com...let it start playing music.
Then check your home dir for a new folder called "pand_ts", in it should be all the mp3s that Pandora has downloaded so far, titled properly and with good id3 tags.
As an after-thought, this might work in Cygwin...no guarantee, though. Anyways, enjoy!
Edit: Save the file as "pand_ts.sh", or the first time it runs, it'll overwrite itself with an mp3...not very useful. Sorry.
Edit 2: Not gonna work in Cygwin...just tried in windows, and the windows version of Firefox is WEIRD. I can't even figure out the cache file locations...