There is a post from element14 which has been on the frontpage of this site and also on the element14 site explaining the reasoning behind the registering: to be able to give people realistic lead times when they convert their interest into an order
The only way to get a Pi quickly is to buy one on ebay at many times face value. Really though ebay prices are so high that unless I really needed a Pi (say I was going to design a case round it) i'd probablly buy a better board instead.
If you are prepared to wait a few months then I would do as RaTTuS suggests and register your interest with both RS and farnell.