The following text is copied and pasted from Tech-Recipes.com:
Pandora is an amazing music service. If you want to actually save the music to your hard drive to keep forever and forever, these steps will allow you to do it easily. Burn straight to mp3 with tags, titles, and sorting intact. Brillant!
You need firefox as well.
1. Go to pandora.com and setup an account.
2. Download and run Pandora's Jar. This forum post has the latest installations.
3. Click the Extract All Files link to uncompress the files to a directory on your computer. I use c:\pandora
4. Goto the directory that contains your downloaded files (c:\pandora)
5. Double-click on pandora.jar.
6. The file will launch and you will see something like:
Attempting to lauch on port 80...OK
[ready, lets grab some MP3'S!!!]
7. Visit http://localhost in firefox
8. Firefox should load with Pandoras Jar version of Pandora
9. As you listen, the mp3s will be created in a directory called mp3 in your original pandoras jar installation directory (c:\pandora\mp3)
Major props to Hak.5 for these directions. I've been following this thread for a while now. Somebody requested that these directions be condensed into one place so I posted it for everybody to enjoy.