>Thanks Costas, but I'm not sure I want to put business information "out there" for prying eyes. Didn't Microsoft's Hotmail recently have a bug exposed that permitted anyone to log in to any account?

I'm currently testing a MTA for Linux that includes web-based mail that might well answer your concerns. It's called Courier (www.courier-mta.org) and besides it's other benefits, it's Open Source.

Just a thought.