Note: This post has been updated to include a link to a coverage map.

Editor’s note: MG Siegler covers the high-tech industry for VentureBeat. He’s filling in for LTW Editor Rick Smith today.

SILICON VALLEY – At last month’s World Wide Developers Conference, Apple’s chief executive Steve Jobs did an onstage test of the iPhone 3G download speed versus that of its 2G predecessor. There was really no comparison, the 3G model blew the other one away.

But many in the audience, myself included, really didn’t find the 3G speed all that impressive either. That should soon change.

When the iPhone 3G launches next Friday, AT&T’s 3G network will be ready with download speeds of 1.7 megabits per second. That may sound good, but that is also the maximum, it’s probably unreasonable to expect speeds of that nature at all times. This means that those of us used to broadband speeds are still likely to be at least slightly underwhelmed.

However, within a few months of launch, AT&T hopes to increase those speeds four-fold, Bill Hogg, AT&T’s president of wireless network services recently told Forbes. Such speed would then be comparable to broadband and should take web browsing on the device to a level beyond the already high level it is currently at.

All of this of course only matters if you’re living in an area with 3G coverage. If you’re in or around a big city in the United States you’re probably fine, otherwise be sure to check out map link with this post. Right now, AT&T says 3G support is in 280 markets and it hopes to increase that to 350 by the end of the year.