I was wondering how to get some of my mame games to fit in screen. They are games like Donkey kong, galaga and Pac man. I am running an old version of mame and have went thru my games to re-adjust them for my arcade vga, but these ones do not have the right resolution to fit right? 
The games you mentioned are all vertical games, and they will ALL look good on a horizontal monitor in 352x288 from an arcadevga, so long as your monitor can handle the resolution. Galaga (and many other games ) has exactly 288 vertical lines, so you might find that you lose a few lines at the top and bottom, depending upon your monitor. But this is acceptable, so long as you can see most of "HIGH SCORE" at the top and "FREE PLAY" or "CREDITS #" at the bottom.
For vertical games with more than 288 vertical lines, eg "The Speed Rumbler", you will need to use an interlaced resolution (eg 640x480 or 512x448) on a horizontal monitor. This sucks, but that is the way it is. Looks absolutely fantastic on my 26" vertical monitor in non-interlaced 240x384 though!