I just checked out this program and it is pretty cool. Like you say, it is very fast. There are some features that may be useful such as customizable display formats for the mp3s and such, but I understand that you want a simple program and that it was designed for a specific application so this is not really needed. There are two little things though that I would like to mention. First of all, and you may have designed it like this, it does not show up as a taskbar button while the program is running. I know that it is a taskbar icon, but that is non-standard and takes a little getting used too. The second thing I noticed is that everytime you add another song to the winamp playlist, it restarts the playing of winamp as if it emulates a 'play' command. When making playlists, I put winamp in enqueue mode and just double click the songs I want in the playlist. Winamp just adds the new songs. When I do this from Music Search it restarts the current song every time I add a song.
I am not complaining, this is a very fast simple program that does what it is supposed to do, I just thought that perhaps part of the reason you posted this was to get some feedback.