I am a little late coming to this thread, but thought I would put my 2p (or 2 cents) in...
It amazingly didn't take me all that long... not as long as I thought it would do. The first couple weeks were a bit rough, mainly because I was freaking out about all the trouble it takes to even get your name added to your husbands' bank account here, and things like that... just made me feel like a total outsider... I am nothing because I don't own a house, I didn't have a UK license yet, and didn't have a chip and pin card. That and then we were living with my husband's parents... which they are wonderful, and I love them dearly, but when you have been living in your own space and have 2 kids for the previous 5 years... you need your own space and it got a bit much. As soon as my husband got a great job in an area that was good for us (as we happened to be going to church there already anyway), I very quickly found a place to rent, and so we are in our own space, which helps a lot!!! Another thing that helpped was my church family. I happened to be at a church where there were 2 other American ladies attending, one having been here for like 3 years, and the other also having just moved. It helps to be able to talk about similar experiances, like on here! The next thing that really helpped that I found, is that we live in an area that is actually very muli cultural, and it is the norm to NOT hear a "British/English" accent for the entire time you are in the town centre! I don't get people asking me all the time... "Are you from America?"
Home really is where my husband and children are... If I have them, I am happy. Don't get me wrong, I miss my family in the US terribly, but glad to be away from bits of the situations there (long story). I have been here close to 9 months now... and VERY HAPPY and at HOME.