Finally some news iPhone users have wanted to hear for over a year:

MMS messaging is coming…

It was announced a few weeks back and it was yet again confirmed this week that MMS for iPhone will be available today, September 25 2009.

Late morning, Pacific Time, on Friday, the new carrier settings update enabling MMS should be live and ready to download through iTunes.

This will come in the form of a carrier update that you will have to download via iTunes.

But while the news is great, don’t expect to see MMS working on your iPhone as soon as you read this.

The AT&T will be systematically activating groups throughout the day, starting at 10 AM Eastern time. Also don’t forget that to enable MMS on your iPhone you must first connect to iTunes and download and install an updated carrier file.

That is, if AT&T’s network holds up. It is predicted that millions of iPhone users will rush to test the new service today, causing a jam in the network or even a complete crash.

The possibility of this outcome has left AT&T feeling fairly nervous, and according to the Macrumours website:

“Early testing has been a little rocky, with AT&T seeing a fairly significant test outage yesterday that has them rushing to beef up their MMSC messaging servers. Estimates among those working on the project are that traffic on AT&T’s wireless network will be about 40% higher all day on Friday as iPhone users fire pictures and video at one another.”

Let’s just hope the jam doesn’t affect things too severely so we can all finally enjoy the MMS feature on our iPhones.