Yes, its possible to install OSX on a netbook, however, Apple actively tries to stop people from creating Hackintosh's on on non-Mac system. Several of the Snow Leopard 'updates' have been designed to stop the Atom. Good to know their priorities are in the right place.
Yeah, Apple tried to end Netbook hackintoshing with the 10.6.2 update- they purposefully made the kernel not work on Atom. Not a big deal- you can get EFI bootloaders that purposefully patch the kernel on boot to remove this artificial restriction.
The real thing that is killing the Hackintosh netbook market is the fact that all Pinetrail Netbooks (and ALL CULV Notebooks from the start) come with the GMA 4500 GPU with is COMPLETELY unsupported in OSX. In fact, unlike previous Intel GPUs, Apple has specifically avoided this GPU in its real Macs just as Intel forced the GPU down everyone's throat on Netbooks.
I honestly think Intel and Apple did it on purpose, which wouldn't make me so mad if Apple would actually SELL a 11.6inch form factor notebook (and no an iPad doesn't come close to cutting it for me).
If you want an OSX netbook the best thing is either to get a last gen ION Netbook (so either a HP 311 or an Asus 1201n) or a N270 GMA950 Netbook. I personally love how my HP allows for overclocking in third party bios (so its faster than any Pine Trail netbook on the planet), but the dual core in the Asus makes it more future proof.
Either way, I expect within a year that the excitement in the hackintosh community caused by the release of the Dell Mini 9 to have completely faded, and for hackintoshing to get back to its roots- making Mac Pros for thousands less than Apple is willing to sell them for.