The programs are sorted alphabetically, you can change the order by renaming the shortcuts in "IPSMWindowsStart Menu". For example, I have direct access to my inbox, contacts and calender from the home screen so I've shifted them down the list by renaming them as "My Inbox" etc.

You can also shift shortcuts out of their sub-folders so you can make MSN Messenger more accessible for example as it's currently in the "Microsoft" folder.

Bit of an iffy method of doing things (you might have to come up with some interestingly named shortcuts to get the order you want!) but it works for me.

Hope that helps