Basic Flaky Pie Crust but substitute butter for shortening. The key to a good crust is to keep it COLD. It gets it's tender, flaky texture because, if kept cold, the better doesn't melt it all into one blob. Also, try not to work pie crust dough too much, as this builds the gluten, which will make the dough chewy. NEVER use bread flour for pie dough.
Oh, and here's a great tip (thanks D): before baking, brush the dough with a mixture of butter and sugar. This not only makes it taste better, but gives it a shiny, golden finish.