A simple script (in linux, windows or whatever) could do that no problem. In fact, I'm pretty sure something like:

find -iname ".txt" -exec mv -v {} /home/user \;

or

mv .mp3 /whatever/folder/youd/like mv .jpg /repeat/as/many/times/as/needed

would work. Is this what you had in mind? Hope I'm not way off base here.

EDIT: for some reason Hacker News edited out my asterisks and the letters within are displayed as italics. Curious.