Review http://www.slipstick.com/outlook/sync.htm and see if you'll move to Outlook.
I don't know of a program that will synchronize in the way you do with a pda, but there is a good program I use to sync the laptop and desktop. I actually use a program called Express Assist 7 (http://ajsystems.com/). I back up Outlook Express on the desktop, move the file to the laptop and then restore the file on the laptop. It is not as easy as a true syncronization program, but it works well. I always work on my desktop when I am home and only back up to the laptop before traveling. I then, back up from the laptop and then restore to the desktop once I return home.
I hope this helps!