iCal and Entourage
[UPDATE 2005-08] The Text below is rather old. This method doesn't work anymore with recent versions of iCal!!! It may give you a startign point however.Apple released iCal on Sept. 10. A great little piece of software. The only lack for me was, that iCal always wanted to use Mail.app to send out Calendar invitations and such.
Since this happens through AppleScript, it was easy for me to fix. Here's what you need to do in order to have iCal use Entourage instead of AppleScript:
Download these AppleScripts
DON'T use Stuffit to expand the archive because Stuffit can't handle long filenames. You have to expand the archive with some easy commands in a Terminal-Window. If you downloaded iCaltourage.tar to your desktop, simply open Terminal.app and type:
cd Desktop tar -xf iCaltourage.tarThis will unpack 3 AppleScripts into a Folder named iCaltourage.
In the Finder, locate the iCal Application. Control-Click on the Application Icon and select "Show Package Contents" from the Context-Menu.
Navigate to: Contents->Resources AND just drop the 3 AppleScripts you downloaded into thie Resources Folder to replace similary named items.