Zodiac will calculate age and star sign as well as your Chinese Year. Now themed and Chinese Year to year 2043 including Yin / Yang.
http://users.adam.com.au/paulwh/_Pages/misc.html
Added here: http://www.portablefreeware.com/index.php?id=2550
EDIT: ahh, It's donationware, not freeware; found out too late, sorry! However, still a nice piece of software!