Outlook is programmable in VBA, like Excel. And I suppose it's an OLE-compatible program.
So all you've got to do is open the the Outlook object, and run the VBA-code to do what you want in it from Excel.
I must admit I've never done it, so for me it's pure theory. But I found two helpful links with google:
http://www.exceltip.com/st/Basic_information_ about_OLE_automation_using_VBA_in_Microsoft_Excel/462.html
and
http://www.exceltip.com/st/Control_Outlook_ from_Excel_using_VBA_in_Microsoft_Excel/464.html
This is where I should start. I might continue by asking a colleague of mine or buying a good book on the subject, depending on what google has more to offer.
Don't expect to find somebody here to provide you with any custom code you need.
Kees
I have several schedules in different Excel files that I need to export. I need to run the exporter from each file everyday to keep my Calendar up to date. How can I have the macro in each Excel file erase all items from the Outlook Calendar with a given address before it exports my dates? In other words: I run the Macro; it scans the outlook calendar and erases all entries in my Outlook Calendar with an address of "123 Anywhere St"; then it scans my list of dates and copies them from Excel to my Outlook Calendar. I already have the part written that scans my list of dates and copies them to Excel, it's just the erasing part I need help with. Right now when I run my macro to scan and export the dates it simply adds to the Calendar. If I already ran it once then I run it again, I'll have duplicate entries in Outlook. Also, how would I have Excel erase all events in Tasks with a given property (for the same reasons as the Calendar)? Thank you for the help.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic