In a new article with Business Week, Nokia CEO Stephen Elop talks of US plans next year as well as Nokia strategy. While nothing concrete is stated, multiple US carriers were noted (and we know T-Mobile is one of those). In addition, it was revealed that Nokia has tripled normal marketing expenditures for the Lumia 710 and 800 when compared to previous launches by the Finnish company--both a sign of desperation but also perhaps confidence in the platform.
Also worthy of attention is the mention of them being picked up by 31 carriers in six European countries for the Lumia 800, with Russia and Asian markets by year end. A notable accomplishment for an initial launch. Finally, Elop dodges the question a bit about Windows 8 tablets but notes “There’s a new tablet opportunity coming...We see the opportunity...", possibly hinting at future plans (see their experimental flexible display for another hint).
One thing that can be noted about Nokia: they're the 800lb gorilla in the room and we're starting to see them make some movement.
Source: Bloomberg Business Week