Do I need Outlook 7 to install Mobile Device Center?
Nope, working on one test system here with Outlook 2003 - but that is with
server sync.

I managed to get Office 2007 beta to install after a couple of reboots.
Much messing about later, plus uninstalling a load of apps just in case
(including uninstalling Office XP which was supposed to have been
uninstalled???) and it's still the same for me - if I try to install the
Mobile Device Center update, it stalls and never goes beyond 0%. When I get
bored and select to cancel, I get asked if I want to try again or view
missing updates ...
Viewing Missing Updates shows an empty list.
Selecting Try Again tells me Windows is up to date".
Viewing the Update History tells be the Mobile Device Center Beta Failed,
error code 800706BE. I am offered a link for more information, to
http://devices/site/longhorn Clicking the link takes me to an error
"Internet Explorer cannot display the webpage
Most likely causes:
You are not connected to the Internet.
The website is encountering problems.
There might be a typing error in the address.
What you can try:
To try to fix this problem, click Tools, and then click "Diagnose
Connection Problems..."
Retype the address.
Go back to the previous page. "
Seems like a bad link to me ...
Steve