Big discussion on this in the Buzzaboutwireless.com forums run by Sprint. baw - Sprint, some information on 4.5? - BlackBerry Smart Phones - Buzz About Wireless Forum
That is the thread that user jverity put up today that links to all the other threads so all the information we keep getting is in one place and not spread around the board.
They told us on the forums that 4.5 is coming, but couldn't give a date. Also said we would be getting MMS with it, but when I asked if it was true MMS or just an application style way of accessing the Picture Mail server I was told it is actual MMS but we will still get a link to view the picture as well. I hope they don't screw it up and we get MMS the way it should be and not some half ass Picture Mail workaround. Also they made mention of us getting Youtube upload capabilities via some application....again not needed if MMS is enabled properly.
Here's to hoping we finally get something.
**edit for additional information**
Both myself and another member on the buzzaboutwireless forums chatted with the CS via the on website Chat now box and both were told nothing about anything coming this month, year, etc. the CS I had told me to go to RIM and get the OS from them and that was the most current one with no update at all about MMS. The other user got a similar answer telling them to call RIM and ask them about it, but they could buy an 8350i and get 4.6 :/ No mention of MMS on their CS chat.