Hi Sagetim,
Logistically, many things you'll need here are the same as in the USA, and that includes mortgage applications, loan applications, credit cards, house buying processes, getting utlitities sorted etc etc ....
There are 'variances' of course, as what Karin pointed out - have a read through posts here on this website for people who've done it before.
Internet is one thing you cna have right away - mobile as well! so you won't need to get a geographic line from the likes of BT or the cable operators. Look at '3' mobile pay as you go internet - £10 per month - no credit checks etc - (I think the USB modem/dongle is £100 to buy from the '3' shop though - look on ebay for cheaper) so as soon as you land you can be online checking out allsorts of information for the other logistics you'll need.
As for you're house, well that's a hotly debated subject here! - without knowing how much approximately your USA house is, it's hard to say if you can buy here right away - I mean you may be living in a million dollar home - and you may have $500,000 equity - that'd be around £250,000 here which means yes you would be able to buy a home rightaway - especially if that £250K here was say a 50% deposit on a £500,000 UK house! - also depends where in the UK you'd be looking at, in central london, that £500K would buy you an apartment only!

Cars - again, on what criteria are you basing 'why are used cars so cheap here?' - depends which make, model etc etc... supply/demand does come into it as well as well do a multitude of other factors....
If yer want to elaborate a little more, then certainly me and other posters can respond with more focussed responses to help you.
cheers! DtM! West London & Slough UK!