MeowMidi2Mp3 is an easy to use tool to convert Midi to Mp3 at 15 different bitrates as well as Midi to Wav. It allows to change the rate of the output (3 rates available) and the number of channels (mono or stereo). You can load SF2 files in the program that give another sound to your midis. It is also possible to load karaoke files and even to read the lyrics.

The license of this software is Free Trial Software, the price is $24.95, you can free download and get a free trial.