Hello.  I'm having an issue with a microphone buzz sound with iMic.  I
can provide a sample of the sound, specific information about the mic
and/or the Mac, and any settings you ask me to provide you (just tell
me how to find the setting(s)).

Both the Mic and the iMic are brand new.  When I plug the Mic directly
into the back of my machine (no iMic), the sound is muffled and bassy,
but no buzz.  With the iMic, its clearer, but after each word, there
is a static, scratch, distortion sound.  I've tried switching around
on USB ports too.

I'm using garageband in iLife '06 + Tiger.

if your Apple computer has a Wireless card built in it, and are using
a microphone it is very likely to cause a muffle sound or distortion. 
Try to plug in a ethernet cable or disable the wireless and it should
get rid of that sound.

Thanks

You did not mention the kind of microphone you are using.  If it ia
mic that requires phantom power it will certainly give poor
performance.
As an alternative, you could try a USB power mic or one that does not
require phantom power.
Or you could try a breakout box that does supply the needed power.