Vimxmms.tar.gz is a project mainly written in VIM SCRIPT and C, it's free.
Control XMMS from Vim
This is a mirror of http://www.vim.org/scripts/script.php?script_id=28
I found that most of the time the only reason I exit from my Vim window is to change songs in XMMS. This script uses libcall () and a little library I wrote to control XMMS from Vim. You can change songs, change the volume, delete the playing song, shuffle play and pause.