Yes, you are correct that UMA requires a chip. The reason it did not come out with the G1 is because it was developed\released before UMA capabilies were in place with TMo (at least that is what I have been told). Plus, Android being a Google based development, I doubt that any of the Android phones will include UMA capabilities...they would rather it go through Google Voice.

Most new phones with TMO that have Wifi also have UMA. I believe that TMo intends to use UMA as one of their competitive differentiators.

Maybe Nokia decided not to include UMA because it is going more the route of VOIP, but it sure would be awesome if they did. Since they have obviously been working with TMo failry closely on this, I will keep my fingers crossed that it will be included with the N900.

It would be a shame if they did not include it, because it has really been an awesome and highly reliable feature. I can tell you far more reliable and higher sound quality than ANY voip app has ever been, that I have ever used, including Skype and Google Voice.