This was mentioned before, but this time also confirmed with the latest manga tankoubon:
The latest
XXXHOLiC manga volume (volume 12) confirms a new TV anime series. broadcast starts in Spring 2008.
Latest manga tankoubon cover:
http://shop.kodansha.jp/bc2_bc/searc....jsp?b=372364X
News from the anime official site:
http://www.tbs.co.jp/holic/01news/news.html