Does anyone know of a sync program that syncs inbox and outbox with Mozilla Thunderbird or Outlook Express?

Try Intellisync.
http://www.intellisync.com/go/produc...tion/index.cfm

Good luck.

Yep, Intellisync seems to do just about everything, but it certainly does Outlook Express.

A word of caution, while we're on the subject, for anyone looking at using/buying this product - there is an issue with different versions of Intellisync & different versions of Outlook; basically, earlier versions of Intellisync don't work with later versions of Outlook (although Outlook Express doesn't seem to be affected), so your best bet is to buy only the latest version of Intellisync (currently at v5.3, I believe).