UPDATE: BGR is claiming iPhone OS 3.0 will include MMS and Tethering via USB and Bluetooth.

ORIGINAL: Engadget has just posted:

We just got the announcement, iPhone OS 3.0 is coming. Set your clocks, mark your calendars. It's going down March 17th. Apparently, we'll get a sneak peak at the new OS, as well as a look at a brand new version of the SDK.

Gizmodo has the text of the invite up:

Join us at an invitation-only event to learn about the new SDK and get a sneak peek at the iPhone OS 3.0 software. The event takes place at Apple, Building 4, Town Hall on March 17 at 10:00 a.m.

We weren't too far off in our speculation. And with the news coming today, does that put a little pressure on Palm for their own special even (which starts in just a couple ours, with live coverage at PreCentral.net)

Start the count down now folks. And the rumors. What are we going to see?!

[Thanks to everyone who sent this in!]