You are probably best waiting for BBerrySync to go live...see the this site -
BBerysync. They are in beta now - there is a thread on them in the Aftermarket Software forum, search for the "BBerrySync" - I'm in the beta, and once they iron out a few issues it will be a very nice product.
You can try Nexthaus' SyncJE client for Outlook and the Blackberry...(
Products - iPhone Sync, BlackBerry Sync, Palm Sync, Outlook Sync, Mobile Sync)
I played around with that (looked at Schedule World and another public syncml server and didn't find the combincation robust or reliable enough for me).