Soundfonts aren't exclusive to TabIt, they're sort of a MIDI "plugin" that can be applied to programs that use MIDI playback. If you have a Creative soundcard, such as SoundBlaster Live!, Audigy, or X-Fi, then you can search the internet for .sf2 files and import them to the MIDI bank of your choice via Soundfont Band Manager. Next, you simply change the banks in TabIt using the same controller that you use to change instruments, and you will experience playback with the enhanced synth.
For an example, look at my myspace. All four of my mp3s are recordings directly from TabIt, so what you hear is exactly what MIDI playback sounds like on my computer with the soundfonts I'm using.
http://www.myspace.com/bmwgmusic