UK Fiance visa. US to UK

[PPP18]

Hi

i am confused as to how to go about getting a fiance visa, or another visa that may be available to my needs?

I am from the uk i met my partner whilst on holiday in LA last sept (2011), i only saw him for about a day as i was on a trip with a load of friends. He obviously wasnt my bf then, but once i got back to the uk we msg on facebook ever since.
we want to be togther in the uk (he will hopefully move to uk with what ever visa possible). so far marriage is the only possible way.
he is going to visit here first so we can meet again. i am 23 he is 25.
i dont know what to do, what we need, how to go about it..?
we would need to live in my parents house which is where i live atm. i own a house with my brother but we rent it out. so i am a home owner but i rent it out.

i need it broken down, as so many website say different things.

what would happen if he came here on a tourist visa and we decided after 80 days to get married (with no marriage type visa, nothing) ? would we be able to do that, without them saying its fraud?
i know in america if you get married (spare of the moment type thing) after so many days they dont declare it as fraud..

just need a lot of help really.
please dont be nasty about our relationship etc..

[vinny]

A visitor may marry in the UK. However, if there was an intention to marry in the UK to a settled/British person prior to entry, then s/he may either apply for a visit to marry visa or apply for a fiancé visa. Subsequently, a married visitor may apply for a spouse visa and the from outside the UK. A fiancé visa holder may switch while inside the UK.

Subject to MAA.