Experience with Emmigration

So, a friend of mine is thinking of moving out of the US and into the UK.
I'm just wondering out of curiosity, does anyone know what's involved? I mean, I've looked at the main sites that concern themselves with the whole thing but I'm wondering if I might be able to get some more subjective views on how it all happens.
I'm interested in what's involved, how long it ultimately takes, what moving itself is like, cost, that sort of thing. Basically if anyone has any stories, I'd love for you to share them.
I'm just wondering out of curiosity, does anyone know what's involved? I mean, I've looked at the main sites that concern themselves with the whole thing but I'm wondering if I might be able to get some more subjective views on how it all happens.
I'm interested in what's involved, how long it ultimately takes, what moving itself is like, cost, that sort of thing. Basically if anyone has any stories, I'd love for you to share them.