When you bought your bike the store no doubt made some adjustments to make the bike better fit you. In most cases this isn’t enough. Not even close. A full fitting session takes a few hours and more often than not, requires the exchange of various components on your bike including bars, stem, saddle, seat post, and cranks.
Some local bike shops have great fitting services including certified fitters on staff. Alternatively there are independent fitters, and specialists available to you. My current bicycle is a Vitess, and included in the purchase of a Vitess is a full fitting session. At my session we ended up changing the bars and the saddle to better suit my body and my riding style. The impact of these changes was immediate and obvious.
Have a read of this article on fitting, and contact your local bike fitter before the 2012 season. You’ll be amazed at what a difference it makes.