krisace is absolutely right.
i've researched studying in the uk as well, but if you intend to come back stateside, it's far better to study law here.
note in the uk, one doesn't even need a law degree, per se, to obtain a training contract at a law firm.
by the way, getting into oxbridge is no walk in the park. of course, stats vary from college to college, but in the main getting into oxbridge is roughly as difficult as getting into a school like columbia (e.g. ask each college for their minimum GPA cut-off). i believe taking the lnat is necessary, too (not just for oxbridge), although it's not weighted nearly as heavily as american schools weight the lsat. but, again, it varies from college to college, and your chances are probably better if you apply to a mature college (e.g. harris manchester, oxford; st. edmunds, cambridge). apart from contacting each college's admissions tutor, which goes without saying, also try looking at the univeristy-wide as well as each college's alternative prospectus and perhaps the norrington or tompkins tables would likewise prove useful.
as for your specific question, you might consider checking out roll on friday and asking your question there?