Could be your bars too low in relation to your saddle or your saddle could be too far forward.
As always I recommend that you take a look at
Steve Hogg and set up your bike via his method.
Most people will find their saddle too high and some will find their saddle too close to their bars.
Read these topics in this order:
The right side bias
Seat Height, how hard can it be
Seat set back for road bikes
Addendum to road pedals, which are best
Power to the Pedal - Cleat Position
Foot Correction Part 1
Also read "Perspectives on Fitting".[/quote]
Quality, not quantity.