Thanks very much Dan. I don't currently use Sendblaster but now that I know it can be eulated, I might. The organization I'm with has a mix of Windows boxes and Macs, so the more we can standardize things the better.

That looks very promising.

I'm looking for software similar to this: http://www.sendblaster.com/ but for Mac.

Free is of course ideal, or a one-time payment.

EDIT: I forgot to put in that this list is huge: 15,000 people and the list is only going to get bigger.