I'm from Norway and I used the Singular GSM net when I travelled to the US last year. The only problem I had and which you might encounter as well is that my phone was european triband which means 900/1800/1900 and I could only use the 1900 band in the US. While if you got a US triband telephone you will have these nets covered 850/1800/1900 and thus you as well will only have one net to use the 1800 one.
But I beleive it will work, though knowing your phone model number and brand might help

Cobos