As of Nov. 2007, you can attach an external Blu-ray burner (BD-R) to your Mac. Mac OS X Tiger and Leopard will recognize the drive. However, no compatible playback software for Mac (that supports Blu-ray and HD DVD content encryption) currently exists.
Apple's DVD Player (Leopard) supports high definition content playback. However, it does not support support AACS, BD+ or BD-ROM Mark encryption schemes used by encrypted Blu-ray discs. Therefore, playback of encrypted Blu-ray discs is currently not possible.
DVD Player also does not support VC-1 encodes or BD-Java.
Currently, the only real use for a Blu-ray burner on a Mac is for data storage. You will need Roxio Toast Titanium 8 to burn Blu-ray data discs.