So long story short. My BBerry decided to go through the wash cycle.
Now I need a new phone. My question is, if I got a Rogers BBerry, and it
was unlocked, could I use it with a telus SIM card?
Correct. That's because the 8900 (Javelin) is an EDGE device. It is not capable of connecting to the 3G network, meaning it won't work on the Telus or Bell HSPA network. You'd need a BlackBerry Bold 9000 or 9700.