I’ve often puzzled over why MS Outlook doesn’t show the day of the week in the date line in Calendar:

Today I did a search in Google Groups to find out if I could change this (you would think!) and discovered that this is linked the Long Date Format in Control Panel | Regional and Language Options.
On my PC (Windows XP Pro) under “Regional Options” I press the Customize… button, and then select the “Date” tab. At the bottom of this window is the “Long date” box, the default (for the UK) being “dd MMMM yyyy”. When I entered: “dddd dd MMMM yyyy” and clicked Apply I was presented with “Tuesday 18 January 2005”, and on opening MS Outlook 2003 saw the following:

The full list of options can be found on the Global Development section of Microsoft.com. The ‘dddd’ is the code for full day of the week name, while ‘dd’ is the date in two-numeral format. Good stuff!