GolfScript, 70 bytes
;1.2{](.2*.*:a@~@*\a(*@)\@}10 2 32?(:b?*@;\{.@[\].~/\~%10*@}b*;;]("."@
Or, actually, don't. It takes WAY too long. Try this one instead that calculates 5 digits.
Uses the Wallis Product, and a custom integer division algorithm.