The Federal Circuit states: "at present...we...reaffirm that the machine-or-transformation test, properly applied, is the governing test for determining patent eligibility of a process under § 101." Slip op. at 15.
The machine-or-transformation test can be summarized as follows: "A claimed process is surely patent-eligible under § 101 if: (1) it is tied to a particular machine or apparatus, or (2) it transforms a particular article into a different state or thing." In re Bilski, slip op at 10.
Because most patentability issues could be avoided by crafty claimdrafting, the court provides guidance regarding two "corollaries" to the above test:
1) Mere field-of-use limitations are generally insufficient to render an otherwise ineligible process claim patent-eligible. Slip op. at 15.
2) Insignificant postsolution activity will not transform an unpatentable principle into a patentable process. Slip op. at 16.
I am sure that much more commentary will be available soon, but this at least provides some high points. Oh yeah, the ultimate decision was to AFFIRM the rejection by the Board of Patent Appeals and Interferences. The complete opinion is here: Bilski.pdf
Feel free to contact me if you have questions regarding the applicability of this case to video games and virtual worlds as patentable subject matter.