I am looking to switch providers from Nextel to Cingular. When I switch providers I am also switching into a BB from my Motorola i870 phone. What is the easiest way to get the 200 or so phone numbers (contacts) off my sim card & into the BB?

You should be able to put the sim card from your phone into your Blackberry, boot it up, go into the Address Book, click the wheel and click 'copy sim card address book'.....or something like that.

So, even if it is a different service provider, different phone type & brand it will still pull numbers off the SIM card?

Hmmmm.....not sure, but it's worth a try...and you won't hurt anything by trying.
I've only done it with Nextel handsets and Blackberry devices.

I'm pretty sure that won't work, as the SIMs are different, and made for different carriers.

However, look for Motorola Phone Tools...it's like a $5-10 program. It will import your contacts from your SIM to your computer, and then you can use the BB to sync with Outlook after everything is copied over. That's what I'd try.