Hey guys!

If anyone's good with cellphone's and GSM and what not, can you help :)

I'm planning to buy the new HTC Touch Diamond off Ebay since I can't buy it up here in Canada.
The phone works on all  900/1800/1900MHz GSM networks.

I googled that, and in Canada, we work on GSM-850 and GSM-1900.

Im not too sure what that means, I was just wondering, if I was to input a Rogers or Fido sim card into my phone, would it work ?
Does Rogers or Fido have a higher GSM ?