It's a never-ending battle working out which version of Android a particular carrier-supplied phone can be updated to. Motorola's latest effort should make it a little easier to pick which Android update applies to your phone.
The "Home For Upgrades" page is remarkably simple — it looks rather like it could have been coded about five years ago — and just walks you through identifying your country, carrier and device before giving you the good or bad news about your particular device.
Bear in mind that just because Motorola says one thing doesn't mean you can't necessarily look at running a custom ROM of some sort, but if you do want to stay on the "official" upgrade path, it's quite a bit easier than digging through some telco sites. Your Home for Upgrades [Motorola via Ausdroid]