I don't know much about Social Work studies, but when I decided to do my Master's degree over here, the first step was to narrow down my desired location in the UK, then pick out a handful of schools in the area that had the sort of programme I was interested in. Then I sent off for prospectus (what's the plural of prospectus?) and emailed the course leaders to find out if they thought my interests and experience was a good fit with their programme.
I decided to narrow down the area first because I wanted to be near my now husband/then boyfriend, so even though there were some great uni's up north, I wanted to be near London. I ruled out any "ex poly" universities (had a Brit friend look at my list and pick them out) 'cause I was concerned about reputation, and then I had a good look at the prospectus from the ones that were left....
Oh, one really crucial thing - if there's a governing body for Social Workers, find out their requirements before you do anything. I'm studying psychology and the British Psychological Society has a list on their website of schools that they've accredited - if I'd chosen one that hadn't been, I wouldn't be able to register with them....
Oh, and one other thing (
) If you're going to take US loans out to cover your tuition, make sure the school you chose is approved by the Stafford loan people - when you fill out your FAFSA you'll be able to check the list.