There is a neat trick to help export your mail in Entourage 2008. If you drag a folder out of the folder list, and onto your desktop, it creates a .mbox file just for that folder.
This is a good way to move emails from Entourage to many other formats, especially if you’re only concerned about a single folder.
Please keep in mind, this only works for the folder you are dragging. I believe any subfolders will *NOT* be exported, and must be done individually.