Hi Davy - I'm certain you won't be able to just walk in so it's down to either being famous enough that you get a visitors invite
or you will need an accredited press pass. The latter can be a bit of a chicken and egg. You need exposure (sic) to get the pass but you can't get exposure until you you've got a pass...if you know what I mean. Either way, I think a letter/request to the organisers wouldn't go amiss.
Thats just an off-the-top-of-my-head answer and I'm sure we have a couple of members who can give you more accurate advice. HTH