Hey, I've been trying to send some stuff I wrote with VD by saving it as a MIDI so it opens with something like Windows Media Player.  For some reason when others try to open it and listen it's just piano... any suggestions?

Think of a MIDI file as a player piano scroll. It doesn't contain any sounds. If you want that scroll to play a song so you can hear it, you need to install it into a player piano.

It's kind of the same thing with using virtual instruments. In order for your sounds to be played, they need to have a compatible MIDI program playing them. There's a big difference between MIDI and AUDIO. Windows Media Player will play AUDIO files, and it'll probably play MIDI files using your soundcard's built-in GM sounds, but if you want it to play more enhanced, specialized sounds, it's best to record your piece as AUDIO, then open it with WMP.

Check out Audacity as a way to record audio:
http://audacity.sourceforge.net/

Geez.  How do you go about making mp3's of your work?

Like I said, create an audio file (aiff or wav). Then just convert it to mp3 using something like iTunes.