How to set iChat status from the command line?
Just found it myself... format the output of sed as AppleScript and call osascript...

curl -s http://ws.audioscrobbler.com/1.0/user/Da3X/recenttracks.rss |
    grep -m 1 -E -e "         &lt;title&gt;(.*)&lt;/title&gt;.*" |
    sed "s/.*&lt;title&gt;/tell application \"Messages\" to set the status message to \"♬  /" |
    sed "s/&lt;\/title&gt;/\"/" |
    sed "s/\&amp;amp;/\&amp;/" |
    osascript


That's it!