Getting a work visa in the US is very difficult, and most US companies won't even consider a foreign applicant due to the extra bureaucracy involved (they have to prove that they made every effort to find a qualified American, etc) as well as the extra costs (I believe it costs the hiring company something on the order of $3500 to hire a foreigner). Add in that people tend to reject the idea of having somebody fly in for an interview from overseas, and that you miss out on the possibility of a personal recommendation, etc.
There are certain jobs where foreign applicants are commonly accepted, even sought out. Unfortunately you've sort of missed the boat on IT jobs unless you're very highly specialised or skilled, and in any case the Indians pretty much have this job market wrapped up. I vaguely recall that there's a US govt website that shows the current key jobs, with nursing being one of them, and these jobs are fast-tracked through the system and are probably the easiest for a Brit to get.
As an alternative, if you have the money, why not go study in the US? Either study for a second degree or for a Masters in whatever you're studying for now. Technically you're not allowed to look work while studying, however they have a 1-year post-graduation work experience scheme that's meant to be for you to bed in the education you've received, but apparently many graduates manage to turn these supposedly temporary jobs into a work visa. Oh, if you go down the student visa route, do not say that you intend to look for work, even if you're planning to try for this post-grad scheme, since you'll find your visa application rejected.
The other possibility from studying over there is that you can possibly get face time with a potential employer, or somebody who knows one and can put a word in for you. True you can't send out applications without risking your student visa, but that's not to say you can't unofficially ask and have them officially approach you. And of course there's always the off-chance that you might fall in love with an American, etc, etc, etc.
Oh, and if you ever go for a visa interview, make sure you take a book or at least a newspaper - the waiting between interviews gets very, very boring!