[APN] 2006-09-05 [TWAPI] has some experimental (in CVS but not in any release) COM client support.

Example:

    package require twapi
    set ie [twapi::comobj InternetExplorer.Application] ;# Start Internet Explorer
    $ie Visible 1  ;# Make it visible
    $ie Navigate http://www.google.com ;# Go to Google
    after 10000 ;# Wait so you can see it
    $ie Quit    ;# exit IE
    $ie -destroy  ;# Destroy the COM object

See [TWAPI and WMI] for some more examples.