We’re not surprised by this but we sure are glad to see it out so soon!

All you netbook owners, current or prospective, may exhale your sigh of relief.
The support for Atom is acquired by actually injecting a different kernel into OS X itself, so, your talking a pretty serious hack. Rest assured, most hacks can be fine tuned to make it much easier and or automated.
We can thank the hacker teateam for this gem. He can be found on the InsanelyMac Forums

So here’s to hoping Apple leaves the door open to Atom users in 10.6.3 and showing us how great of a company they really can be.