Looool, yeah they'll also write to you through the post, so don't panic when you get that through - I did that, **** myself literally aha!
Well one project, with 2 folders was A2 sized, really big, and so heavy, so avoid that if you can lol. Others were A3, it's all you need mate. What kind of work have you already got? What stuff you gonna put in your portfolio? If you can, try and have some research / analytical stuff, or even a few pages like a scrap book, just to show where you got the inspiration from. What stuff you working on?
My mate who's gone for it has a really good portfolio, and her interview is on Weds. She's organised it in a really neat way, in one of those leather big professional case things, but I didn't bother with anything like that, I just bought my graphics folders as normal lol. She's been to LCF to do a make-up course and has a little bit of stuff on that, but she's bringing most of her photography work (where she's had to dress the subject, or put make-up on them, etc)... X