KeySuite has become my Palm Outlook companion. I was along-time Agendus user (dating back to the original Newton Message Pad when the program was called Acttion Names) but found the inability to sync with all of my Outlook fields and categories pretty frustrating.
KeySuite is my choice in the Outlook workalike category.
I wrote a review of the program for PDA 24-7, a great web site for Palm users: http://www.clieuk.co.uk/ks1.shtml
You can download a trial copy of KeySuite here: http://www.chapura.com/keysuite.php