I'm thinking about applying to Cambridge or Oxford but I am worried about what I'll need to do - is there a site that could help?

Yes, start by checking out the Oxford and Cambridge University websites - www.ox.ac.uk & www.cam.ac.uk/. You'll find loads of useful stuff, on everything from how to choose a college to what to expect at interviews. 

 

You could also look at  www.oxbridgeapplications.com/  a free website run by a commercial company - where you can register and access free online resources and advice about applying.

There are also specialist books in your local Connexions library and both Cambridge and Oxford post information about their admission tests on their websites.

  

How to apply via UCAS