Sprint now joins Verizon in taking jabs at AT&T's network and the iPhone, offering an "iPhone 4G" in their latest TV spot via their Overdrive WiMax hotspot (think 4G MiFi).

Sprint claims the best solution to AT&T's supposedly slow 3G speed is not the next generation of iPhone (which won't be called the iPhone 4G due to LTE networks not being deployed for a year or two yet), but rather your current iPhone connected via WiFi to their beefed up 4G WiMax network.

So, with Verizon targeting the iPad via MiFi and now Sprint going after the iPhone via WiMax (when they could be focusing on their own devices like the Droid and the Palm Pre) are they hoping to prop up the modem business by surrendering device mindshare to Apple?

Thing is, last we checked AT&T has the fastest 3G data speeds available on any US carrier and that's good enough for us. But for those unfortunate souls out there with less than desirable AT&T service is this something that you would ever be interested in? And if you're already tethering your iPhone to a Sprint Overdrive, what kind of speeds are you getting?

Watch the ad after the break!

YouTube link