In the UK you just tell everyone that you'll be going by $MarriedName. You may need to show your marriage certificate to people like the bank but most people (dentist, vet, GP office, work) just took my word for it.
Unless your passport was issued within the last 12 months you will have to pay for a new one. If you want your visa in your new name in your new passport you will also need to pay for a new one (seriously). Otherwise you would carry your new MarriedName passport along with your old passport with the visa and show both. As for the rest, I've not done it so I haven't the foggiest idea
I havent changed my name in my passport either but I am considering doing so before I apply for ILR next summer.