Jaime, I done the Silverstone Half last year, it was also my first 'proper' race, as before that I had just spent years running round parks and beaches. However, to answer your questions:-
"Any equipment/clothing (at the moment I run in regular canvas running shoes, a long sleeve top, thermal top, regular sports shorts and a beanie type hat and gloves) recommendations? Is it advisable to use a pedometer type device, to measure times/distances/pace etc?"
Get yourself off to a running shop and get fitted out with some proper running shoes before you get injured! Depending on the temperature (last year was about 10c) I would wear a t-shirt (not cotton) and shorts (ditto). They will have pace setters there so no need for a Garmin, just stick yourself close to one at the start (can't miss em, they hold up boards with 7min, 8min, 9min etc etc, and the time relates to per mile), this will allow you to maintain a steady pace.
"Any training advice? How many days before the event should my last run be? How many miles should I be aiming for in training?" I'm not the best qualified to answer, but I'm aiming at running 13miles 2 weeks before, and then easing down with maybe a 9miler the week before, and a few 4 milers during the week leading up to it, just to keep things ticking over.
"Do the majority of people raise money for a charity at these events?"
Not sure, I didn't, might do this year.
"Any general running advice?"
Get there early otherwise you can miss the start (I did) due to the traffic, and then spend the rest of the race threading through the field wasting energy (as opposed to running at a comfortable pace). The last 2 miles is a killer as its going the wrong way up hanger straight, at the top (becketts) there were a couple of casualty's getting first aid, so even though you're close to home, make sure you have a bit left for that final climb!
Good luck
Murdoch
Edited: 10/01/2012 at 19:10