Adobe has posted for download beta 4 of Lightroom for Mac and Windows (registration required), and given the program its official name: Photoshop Lightroom. Beta 4 brings feature parity to the Mac and Windows versions, adds RAW processing support for the Nikon D2Xs and Sony Alpha DSLR A-100 and preliminary RAW processing support for the Canon EOS Digital Rebel XTi/400D and Nikon D80. The Beta 4 release notes detail other changes.