Many of my most favorite songs are from this site and I have only been able to listen to them through the site. However, since the aforementioned design change, the site has really died down in my opinion and I was fearful ever since that it would simply go down some day and vanish - taking my songs and playlists with it.
As counter-measure I've written a java console application to extract playlists and songs from thesixtyone. It uses Selenium to remote-control a FireFox instance that uses the normal user-interface to play songs and read in playlists.
I've uploaded the code to launchpad: https://launchpad.net/t61extractor/trunk I've tested and used it myself and it runs alright.
This was a small weekend project (or rather two weekend project) that I did a few months ago but I only found time now to write about it.
The code should be mostly self-explanatory and it's not a lot of code either.