According to an article published by Marketing Charts Samsung has maintained its lead in the mobile devices used by 234 million subscribers in the US. 
Below are some of the rankings:

• Samsung - 22.1%  
• LG - 21.8% share
• Motorola - 21.6%
• RIM - 8.4%
• Nokia - 8.1%

What I find interesting about these numbers is that Nokia is the most popular brand in the emerging nations but it is lagging in the US.  And despite all the buzz about iPhone other phones are still in the lead.
On the carrier front Verizon is maintaining its lead at 31.1% followed by AT&T at 25.2%. 
On the content front 64% users have used text messaging (fits along the strategy Microsoft has for its Kin phones), 31.1% are browsing the web and Apps downlodas have increased to 29.8%.  Social networking and music downloads have also increased.