Cartoon type diagram

A 950 by 550 (w x h max) pixel explanatory diagram for a 'peer to peer' currency exchange website. Diagram should show new users how the service works from a top level point of view.

http://www.pendlehouse.com

Pendle House is a new currency exchange service. It operates by letting users pick a currency exchange rate they would like to change their money at, put it up in a market and wait for another user to take the offer. Conversly they can accept an offer already on the market. Its purpose is to bypass banks, bureau-de-change providers and other 'middle men' type institutions and allow people trade directly with each other on an open market. A 1 minute video explantion is available here: http://www.pendlehouse.com

I need a single funky diagram to explain to new users how the service works. This diagram should include the following:

* Money needs to be transfered into their account in the Pendle House system (bit like Paypal)

* Users can choose a rate of their own to sell their currency at

* Or else they can choose a rate thats already available from another customer on the market.

* Money can be transfered out of the Pendle House system again after the exchanges have been completed

* Its got a global reach - Users can trade with other users from anywhere in the world

* Its annonoymous - Users will not know who they are trading with.

- Easy on the eye and on the mind, meaning not too overly complicated. 
- Try and use the full 950 by 550 pixels available
- Very open to funky or fun ideas on this.

- Too formal. Want to avoid anything thats too corporate or boring
- Diagram can be no larger than 950 by 550