Sprint/nextel are CDMA.
To put it down shortly, you have two types of phones: GSM and CDMA.
If you want Telus, go with any CDMA phone. It's usually in the phone's description or you can always ask the seller on ebay. You can probably also buy one in the phone section.. there's gotta be a few.
EDIT:
GSM - Fido, Rogers, Orange, AT&T, T-Mobile, etc.. Pretty much anything with a sim card that you put in the phone.
The rest is CDMA - Telus, Bell, Sprint, Nextel, Solo, etc.
Hope it helps.