Oneiric Ocelot has just made a big jump from Linux kernel 2.6.39 to 3.0 version, so, if you use/test Ubuntu 11.10 ALPHA 1 you should receive the new 3.0 kernel.
Regarding the 3.0’s newness, Linus Torvalds explains that there is “NOTHING. Absolutely nothing” new, 3.0 “is *just* about renumbering“, but “we have the usual two thirds driver changes, and a lot of random fixes”, so “no magical new features”.