linux-libc-headers are mantained by mariusz mazur, but if he continues working on that project (seems he suffered a serious hit in his personal life) it's supposed not to have a new version of linux-libc-headers until... 2.6.16 (supposedly 2.6.15 but as you can see by yourself, there's no new version... yet)
anyway, take a look at the page of linux-libc-headers on a regular basis, just in case
ep09.pld-linux.org/~mmazur/linux-libc-headers/
greetings,
Julio