Depending on what name it is, it could be a yes or a no, the same with any other extention. The question is too broad to answer properly
Check out http://namebio.com for the recent sales of domains. Dot us isn't selling for as much as dot com, but the right name could bring you a good amount of money.
Really depends on what the name is and how large the industry for that name is. The only bad thing about .us is it's pretty much limited to US companies, therefore you limit yourself with possible buyers.