The TechZone has an article about Blu-ray Vs. HD DVD.
It has been two-and-a-half years since next generation DVD was first announced (actually CES of 2003) by Sony. To regain its position as the guides to the future, the DVD Forum adopted a different blue ray technology approach AOD (now known as HD DVD) and thus even before present DVD products had gained widespread use, the warlords battle for royalties began anew. While the two "standards" share blue laser technology - shorter wavelength and a more precise ability to focus the laser - there are enough differences to make it obvious to even the most casual Tech Watch reader to realize that a compromise solution will be difficult. Head over here to read more.