I asked a similar questiona while back. I now use Fenwicks FS1 as recommended by Harryburgundy. It smells brilliant too.
http://www.wiggle.co.uk/p/cycle/7/Fenwi ... 360035727/
You can buy 1 litre bottles. I pour it in to empty Flash bottles with spray heads as I am tight.
I dilute it 2:1 for cleaning the chain and oily bits and 10:1 for cleaning the rest of the bike.
Instructions:
Spray on bits to be cleaned.
Go and make tea.
Rub with a brush (I bought a washing up brush just for this purpose though you can just use the one from the kitchen).
Drink tea.
Spray off with hose.
Bike is now clean.
Lubricate bits that need to be lubricated.
I don't like using pressure washers (uness you're at Mayhem and you get a free bottle of chain lube each time you go to the muc-off stand).