HowTo? Fixed / Singlespeed conversion from an old bike

Now I would love some advice/recommendations on how to turn this frame into a fixie for riding around the flats of central London. Cheap as possible.

Everyone always says this. That's what I tried to do with my first conversion.
It took me about a month to get bored of the rusty old steed and develop my appreciation for shiney things.
My bank balance has never been the same since.