Despite the fact that no firm release date has been established for any future iPhone, the Wall Street Journal nevertheless reports that the iPhone 5 will arrive on Sprint’s cell network sometime in mid-October.

The source also apparently claimed that the iPhone 4 will also be coming to Sprint at the same time, according to “sources familiar with the matter.” With many sources suggesting a late September or early October launch of the iPhone 5, and with reports suggesting the device will be a “world phone” capable of running on both GSM and CDMA networks, I’d be surprised if the iPhone 5 didn’t include support for Sprint right off the bat (if the rumor is even true at all).

If true, this would mean that Apple’s iPhone 5 would be available on 3 of the 4 major US cell networks, and if AT&T’s proposed purchase of T-Mobile USA is allowed, that would effectively mean that all major cell providers in the US could then support the iPhone.

The idea of an iPhone on Sprint’s network is nothing new, with several such rumors cropping up throughout July.