Before we get started, its worth saying that there hasn't actually been any third party confirmation that this "crack" actually works...
But that being said... I found out about this earlier but did some research before posting this time as the last reports of a Blu-Ray "crack" on PS3 I posted were bunk (thanks to news reporters who didn't do their research).
Here is the OP of the utility maker:
http://forum.doom9.org/showthread.php?t=119871
Unfortunately for us, even if it did work though as described by the author it does not "crack" HD DVD/Blu-Ray's AACS in the same way that we think of DeCSS or DVDecryptor "cracking" DVD's.
Looking at the post of the author of the utility, it appears one of the recently released software HD DVD/Blu-Ray players did not sufficiently encrypt the actual movie title keys in memory when playing back the movie (let's say PowerDVD 6.5 in this case). Therefore, this utility allows the user to "decrypt" and play current movies (with some footwork - you need to find the keys for yourself - it doesn't just run automatically) using a title key found within an active PowerDVD 6.5 session memory dump - however future HD DVD/Blu-Ray movies & drives will then add PowerDVD 6.5 to their blacklist and PowerDVD 6.5 will be unable to access future HD DVDs and therefore title keys will no longer be obtainable using the insecure player software. Your drive will be automatically updated with the latest blacklist via standard movie discs. PowerDVD 6.5 users of course will need to upgrade their software since it will be considered an insecure player - I'm sure this is one of the reasons ethernet jacks are mandatory in HD DVD players as even if one of the standalones players is found insecure and blacklisted it can be easily updated w/ net firmware.
Therefore, if it is legit at best this crack only allows hackers to "crack" both HD DVD/Blu-Ray content released this year. Next year's releases will revoke PowerDVD 6.5's decrypt deviceID and hence everyone will lose the method to find the title keys using this method for HD DVD/Blu-Ray discs authored/reauthored in 2007... Unlike CSS (which had a very limited set of keys), using this method with AACS is more of a cat-and-mouse game, with each new movie able to ban an unlimited number of insecure players/devices.
When AACS will really be cracked is when they are able to bypass player revocation, but that has not been accomplished... yet