I found that you can use “It
 

I found that you can use “Itunes” to convert midi files to MP3. You can also edit the MP3 info to show anything in the ID tag. It does a better job than most midi to mp3 converters I have tried.

For anyone's future reference, here's how you do it:

Open iTunes
Click "Edit" in the menu
Choose "Preferences"
Click the tab labeled "Importing"
Change the "Import Using" value to "mp3 Encoder"

Then, click on "File"
Click on "Add File To Library"
Navigate to the location of the midi file, or whatever format file

Then, select the midi file in the Library
Right click on the midi file
A menu will be brought up where you can "Convert Selection to mp3". Choose this.

To change your iTunes back to its original Apple format (if you want that), simply follow the following directions:

Click "Edit" in the menu
Choose "Preferences"
Click the tab labeled "Importing"
Change the "Import Using" value to "AAC Encoder"