How can I sort MP3s to folders based upon tag info

Hi

I have a large collection of (legal) MP3s which are tagged with artist, album, date, genre etc

They're not organised in the most efficient way so I'm looking for a programme to sort them into folders.

I's like to be able to select a folder full of assorted MP3s, tagged with artist and album and sort them into folders like, for example:

\Artist1\Album1\tracks
\Artist1\Album2\tracks
\Artist1\Album3\tracks
\Artist2\Album1\tracks
\Artist2\Album2\tracks
\Artist3\Album1\tracks
\Artist4\Album1\tracks
\Artist4\Album2\tracks
\Artist4\Album3\tracks
\Artist4\Album4\tracks

and so on.

Ideally I should also be able to select other tags such as genre and year as part of the folder structure.

The programme should ideally be freeware or open source.

Can anybody suggest a suitable programme?

Thanks in advance

-Tony