I bought / jailbroke and did some "other hacking" of my iPhone for use on the Rogers network only weeks ago. The upside is that I pay very little for data because of all the research I did, but the downside is that I now have to sell my phone in a hurry because I *know* the 3G phone is coming in June, and Rogers wouldn't be bringing in the iPhone without that service. It wouldn't make any sense.
Visual voicemail, here I come... And not worrying every month that Rogers might figure out what I've done. *sigh*