Originally Posted by gdpmumin
There's not a chance I would delete the contacts in Outlook. Not a chance. I would rather wipe my handheld (which isn't a bad idea anyway in this case) than delete my contacts from Outlook.
But, to answer the initial question, I would suggest exporting your contacts and calendar to back them up, just in case something goes wrong.
Yeah, it can go either way...deleting from one is no different than deleting from the other as far as I am concerned (so long as you have a backup, as you mentioned).
I just did the same thing...switched from BES to BIS. I did it specifically to move away from Outlook though. I wanted to be free of Outlook before I buy my Mac in a couple weeks (Entourage sucks).