removing old Sharepoint sites from meeting request area

[Jackson]

I'm currently using Outlook 2003 and Windows Sharepoint services to create
meeting workspaces.
My problem is that I had a lot of old Sharepoint sites that are listed
whenever I create a new Meeting Request -> Meeting Workspace-> change
settings(right panel) and select a location. Is there anyway of getting rid
of the old Sharepoint sites that are being listed in "select a location"?

Thanks,

Jackson