[MV] Sennheiser headset microphone and/or the Sennheiser MD431 with iListen

[Kerry Bowen]

Has anyone used the Sennheiser headset microphone and/or the Sennheiser 
MD431 with iListen?  I need to be sure that I have the best possible 
chance of success when I start to use speech recognition in my office 
workplace and these 2 microphones are featured on a specialist 
retailer's website. I use OS X 3.4 right now combined with a G4 AlBook 
1.5 gHz. i've also considered the MacMic for starters-worth a try?

TIA for any feedback