My dbx Driverack PA (
http://www.driverack.com/PA.htm ) with analyzer mic will be here this week and I should be able to use it this Thursday. It has an automatic room equalization system and feedback suppression as well as a host of other functions.
I will keep you posted how well it works.
This thing cost a bit $499 at Guitar Center but it answers a lot of questions.
I will use it to control the output from the board to the amp and I am also using a Behringer MDX 4600 4 channel compressor/limiter to save my ears (and those of the audience) from the people who either have no idea how to use a microphone or just like to scream at the top of their lungs.
This and all of the other stuff I have bought recently should make for an awesome sounding system. Then I can go back to upgrading my music collection.
Jon