The Nexus phones are a special case. The updates for those come straight from Google. For every other phone, the phone's manufacturer needs to release the update to the carriers, and the carriers send the OTA update out when they're ready.
You can get a US data add-on for your account, but it's a lot of money for very little data ($30 for 10MB, last I checked - depending on your usage, that may not even cover your email). You're better off getting a prepaid SIM from one of the US carri...
The Liquid E got the Froyo update in November (so lag time there was about 6 months). Not so bad, compared to other manufacturers and carriers. However, as Rogers adds more Android phones to their lineup, the time required to update any specific phon...