There are several UK based bike component dealers that have much better prices than anyone local. Most have free shipping above a specified order amount. They will quote in US dollars if you make that choice on their web site.

Along with Pro Bike Kit already mentioned, I've also dealt with Wiggle (www.wiggle.co.uk) and Ribble (Buy Road Bikes & Parts at Ribble Cycles | Online Bike Shop) and had very good delivery times and costs with all three. And, yes, those are really their names.