Intel has plans to get rid of current Atoms in a relatively short time frame. Intel has already made decision to stop selling Atom N270 in Q2 2010 and put it in so call End of Life status.
It also informed its partners about Product discontinuance notice and after this period, the new Atom N450 with all integration should take over.
We are quite sure that you will be able to buy N270 based notebook even after Q2 2010 as partners can buy and stock many of these chips. This can give you an idea that there might be two platforms selling at the same time, with a good chance that N270 based netbook 2008 machines might end up at least a bit cheaper than the brand new ones.