AppleMacster I bow to your many years experience. I am a mere beginner by comparison!
I agree MSN Messenger for Macs obviously hasn't been supported by MS for years, I tend to use one from Mactopia which keeps the little Chambos happy enough. No matter how much I try I can't seem to get them to just use Skype or iChat, no they would much rather tap away!
I agree that turning on the firewall is perhaps strictly speaking unnecessay if you have a good router. I recall though that some were better than others, and of course if you have the misfortune to be using a USB modem then the inbuilt firewall is probably your only line of defence. It's a belts and braces thing for me, router and firewall, although the firewall will need to be turned off if you want to share files wirelessly.
I will go and have a look at this Parellels emulator, and see if it will do the trick.
By the way is just me or does Google Earth run a whole lot better on an the dual core chips as opposed to my iMacs G4?