2009-07-04 Sat - Dunwich Dynamo 2009

I wouldn't sweat too much about training.
Anybody can do that distance.

I'd say:

Eat well in the days preceding the ride.
Service your bike prior to the ride.

Take decent portable food and plenty of fluids. Eat and drink regularly, before you get hungry/hit wall etc.
Wear padded bike shorts (under your normal cycling attire or whatever)
Take some decent layers.

Get/borrow decent lights and or ride with someone who has them, take spare batteries.
Bring a selection of tools, split the load with your friends if needs be.
Bring spare chainring bolts and a length of chain, if not for you, someone else might get caught short.
Bring a few spare spokes.

Most importantly: Do not worry about being fast, pace yourself. You will get there in the end and you certainly will not be the slowest in.

Fat 15 year old girls on Halfords dual-suspension mountain bikes did it last year so don't over-engineer your anxiety, you'll be fine.

Nice one MA3K!

And as for pacing, if you've not done this distance before, don't follow MA3K.. he will smoke you and leave your quivering body for the locals to find. ;)