Falling Leaf Systems has stareted up the Alky Project (currently in alpha), which aims to liberate DirectX 10 gaming from the confines of Vista and bring it first to Windows XP, and then to Linux and OS X. The project plans to do this by building a converter that can take in a DX10 game executable and spit out a modified version that can be run on a (non-Vista) target OS. The target OS must be x86-based, which rules out the PPC version of OS X, since the converter doesn't do any binary translation. To help fund the project, Falling Leaf has set up the Sapling Program, which lets those who donate $50 get access to development builds and other perks.
Ars Technica had very little luck when to view Alky's DX10 demos under Windows XP. The recommended DX10 tutorial did not run successfully, even after installing 1GB of required siftware: Visual C++ Express Edition, the DX10 SDK, and the Microsoft Platform SDK for Windows Server 2003 R2. Clearly, Alky has a long way to go before even XP users, much less Mac and Linux users, can easily convert DX10 games for use on their platform of choice, but the fact that the alpha does allegedly work for some folks is promising.