Well I can't find my guide, but I'll do a brief version anyway. I'll try and go round the circuit from the starting grid, in some sort of order. So...
Start/finish straight:
This is a good place for watching/photographing race starts. Also good for general on the grid stuff so as teams and cars getting ready. You don't need a massive lens for this really, as a wide picture of the cars on the grid will still look good. Once the race starts you can shoot them heading away to the first corner (from behind), and then head ons of a train of cars coming through the final chicane, obviously you will need a longer lens for this.
Riches:
You can spectate from the inside of the corner, good for panning shots of them entering, going through, or exiting the corner. Good to watch the start from too, and watch battles into the first corner and down to Sear. I'd probably go hear for practice or qualifying though - if they are in the morning the light is nicer, and there is probably better places to watch the race from.
You can't get right down to the corner on the outside, but you can do some rear shots of them going into it.
Sear:
Sear is inaccessible from both the inside and outside of the circuit as a spectator. I went once when signed on (to the outside), and it was a waste of time!
Revett Straight:
You can view most of the way along it on the inside, but bear in mind most cars will be going bloody fast at this point, and hard to capture. Get down to the bridge end, and you can probably manage some pans and head-ons.
The Esses:
You can do loads of stuff at the Esses from both sides. It's a pretty good place to watch a race from, but I'd be more tempted to go there for practice or qualifying - you can see more from other places in the races generally. On the outside you can pan the cars all the way through the lefthander, and then do a rear shot into the tight right hander, often wheels in the air over the kerbs. Or go further round and a do a head on shot of them in the right hander, or pan out of the Esses (you'll need a long lens if you want a close up though!). On the inside you can do a head on or a pan through most of the corner - longer lenses (400mm+) need for some bits! It's also a good place to capture cars going off - they easily overshoot the first bit at the end of the straight, or carry too much speed into the slower right hander.
The Bombhole:
Another place that it's probably better to go for qualifying, and the only corner that you can get a better shot at as signed on media (well as well as the outside of the first corner). This due to the debris fencing in between the bombhole and Coram, but you can do a pan going in, and a rear shot through the right handed dip.
Coram:
Probably my favourite place to watch from as a spectator - you can see the cars all the way through the Esses, round Coram, down to the chicane, and down the S/F straight to the first corner (unless it's really foggy!). You can do head on shots (with a long lens) and pans pretty much anywhere, it's up to you to decide where looks best in terms of background clutter!
Russell:
Probably the most popular spot to watch from, and like the outside of Coram, as good a place as any to watch the race, either from the inside or outside. For photos the inside is probably better, there's plenty of head on and pan oppurtunities. Don't worry about having a massively long lens to get close ups - groups of cars on a wider lens look good!
That's about it, hope it helps!