Is this possible at all? Has anyone done it? I'm a UK Citizen who is self taught with 5+ years experience developing web based software.
I may have the option of starting a part-time master's degree in computer science... Would this help even without an undergrad?
If you work for a subsidiary of a US company outside of the US for at least one year then you can transfer on the L-1 visa to their US office. Just be aware that you can't switch companies like you could on an H-1B. However, L-1 visa holders can still apply for a green card. Once you have that you're free to change employers.
One technicality: If you work for a big company (like Google) then you're basically guaranteed to get the L-1 after one year since those companies typically hold the so called L-1 blanket. Otherwise it's a more involved process where you might get rejected.
I have friends who are currently on an L-1 in SF through big companies (= L-1 blanket holders) and getting it was basically a formality.
The L-1 also has the advantage that there is no annual cap like there is on the H-1B. You get it or you don't. No lottery. One big startup that I interviewed with opened up an office in Vancouver specifically for H-1B rejects to get them to their main office in SF through the L-1 one year later.
More information on Wikipedia: http://en.wikipedia.org/wiki/L-1_visa