Hi there,
I've not got any links to hand (Chad Gray had an excellent site, but it seems to have vanished), but you need the pin-out of the JAMMA fingerboard (the edge connector on the MVS board). And the pin-out of a SCART connector (to plug into your TV).
Search google or somesuch for : 'JAMMA pinout' and 'SCART pinout'.
The JAMMA connector takes inputs for the controls (I hacked a SNES joystick for this), the coin slots and the test/service buttons. It provides video and audio outputs.
You need to connect the video outputs to the SCART connecter. Red, Green, Blue, Video Sync and Video Gnd I believe. This can go straight into your TV.
You musn't connect the audio outputs to your tv though! They are already amplified, and can blow up your tv's speakers! Just hook up the sound outputs directly to a small speaker.
Oh yeah - And you need 12V, 0V and possibly 5V and -5V to power the MVS board.
Don't bother buying an arcade power supply, just use a PC power supply, as it can supply all of these voltages.
There are a few supergun projects out there on the web. Try to find some. But if you have any questions, I'll try to answer them.