I have a new web application that’s going to be released soon that lets you convert music online. Titled media.io, the application will be very easy to use:

• You upload your music. At the moment, MP3 and Ogg Vorbis are supported, but feel free to ask for more :-)
• You chose the output format (again, MP3 and Ogg) and the output quality.
• Your music is encoded.
• You download it.
• Everybody’s happy.