Debian has a very strict policy on free and legal software. This helps keep everyone honest, but sometimes a pragmatic approach is called for. MP3 is a file format that is patent encumbered - but also in universal use.

I could use the supplied Ogg Vorbis tools but then my music wouldn't work everywhere I want it to.

So I want to install Lame which is only available in source.

http://sourceforge.net/projects/lame/files/

Download and extract