My school organises a 2 day trip to oxford and cambridge. We also have had 3 visits from a Cambridge admissions tutor and a mock interview. The school spends a lot of time helping Oxbridge applicants and I'm very grateful for that.
Although my school is a very working class state grammar school, they do place a lot of emphasis on Oxbridge applicants. They start the whole process for potential candidates in January in the Lower 6th, we went a school nearby to us for a talk on appying to Oxford and we have a Cambridge speaker visiting next moth to talk on the same subject. Later on in the year around April/May time we go to Oxford for two days and about a month later go to Cambridge for two days also. Then several weeks before interviews we recieve a mock interview from an admissions tutor at nearby Liverpool uni, and finally an interview with the head of the department for the subject you have chosen to apply to read, for some last minute tips. Extra AS courses are also provided to beef up applicants UCAS forms such as Critical Thinking. I am suprised at all the effort that is put in when usually only 10 or so apply, however it must be very important to them, for prospectuses etc. However we are all very appreciative of all the staffs efforts!
I am getting quite a bit of help, again because it's a private school. There are about 25 students applying this year, which I suppose is average at my school. There is a trip arranged on the main open days for both universities, with accomodation in a college. I attend an English tutorial once a week with my teacher, experienced in marking both English and Theatre Studies A-level papers. The Head of English attended Cambridge, and another teacher went to both Oxford and Cambridge. However, as good as it appears in these respects, I must say that my AS English set are crap at it, and tend to laugh every single time I make a point (which is often, considering they say nothing). So even where I go (which, to be honest, in the private sector is no great shakes, at least fee-wise), it is still very doubtful if I'll get in or not. I suppose it all depends on the individual's talent; the staff are presumably well trained at spotting a good candidate.
If any pupils in my school said they were going to oxford they would have had them sectioned and locked up in a mental home.