Since there wasn't a working one, I wrote a small plugin for picard that automatically fetches album and track information from tango.info.
Just put it into your plugin directory, and if your tracks have
barcode tags, it will do all the magic for you. It currently sets
vocal(singer/s) metadata, but it can be easily adapted for other fields.
The code is here, including usage instructions.
Update: The plugin has been merged into picard-plugins, which means you should be able to download it directly from the picard website. It should be included in the next release of picard, which will be version 1.4.0.