Sorry I don't have my Mac right now, but I think the only thing I did was copy the Profiles folder on to my thumb drive and then copy it on to the mac. I don't think I had to convert anything at all, maybe just redownloaded some of the extensions... I'm not sure but you could see about Febe for thunderbird, I know they have it for firefox but I'm not sure if the one they have for tb is for the version of tb that is being used (which doesn't make sense to me). And if you just want either your firefox or tb to store to a diff place, just change the profiles.ini and you can find that info on how to change that on the net.
Thunderbird stores your user data in one of the following locations:
Windows 2000, XP Documents and Settings\<UserName>\Application Data\Thunderbird
Windows NT WINNT\Profiles\<UserName>\Application Data\Thunderbird
Windows 98, ME Windows\Application Data\Thunderbird
MacOS X ~/Library/Thunderbird
Linux and Unix systems ~/.thunderbird
Also check your firewall settings to make sure that it's not blocking the port that tb uses.
Hope that helps
Tried both those links... no real help there. Anybody else have an idea, or know the trick?
TIM