I was just gifted a free BB 8830. Yes, it is an older model, but not so old that I'm not be happy about using it.

This phone uses "800/1900 MHz CDMA, CDMA2000 1X and EVDO, 900/1800 MHz GSM/GPRS".

I also see from Wikipedia that my choices are Bell Mobility and Telus. However, the phone is "locked" to Telus because I see the Telus logo at the bottom. I think if I wanted to use Bell, I could "un-lock" the device. I thought I recall seeing places on RFD that do this for $5 to $10.

I imagine that I won't need to lock into a contract, since I have the phone already. I imagine that I also need to obtain a new SIM card for either Telus or if possible and desired, Bell.

Does this sound right so far?

That phone will only connect to Telus' CDMA network. Since Bell and Telus don't allow outside phones on their CDMA networks you'd need to use it with Telus. You also won't need a SIM card.

To clarify, I think what you are saying is that the GSM frequencies on the device's radios are not those for North America; it will not connect to Rogers' GSM network here and definitely not the Bell/Telus HSPA+ network.

These multi-band CDMA/GSM devices were sold (prior to the launch of the Bell/Telus network) to customers wanting a phone they could use here, on CDMA, and abroad on GSM, using a Telus/Bell SIM card or one purchased in the country visited. They had their place until a year ago but any advantage is now diminished.

My fleet of devices is mostly 8830's which are now being phased out so I can state this:

It is locked to whatever provider it is branded with. The phone is a CDMA device only in north America, and uses the "Roaming" (Vodafone UK) GSM card only outside North America as the GSM radio is not set for the frequencies that we use in North America.

Bell and Telus as stated to not allow outside CDMA devices onto their network.

You only need a "Roaming" SIM card if you want to use it overseas, otherwise, in North America it is only good as a CDMA device.