Mouse over tag for share icons

Mouse over tag for share icons

Could anyone provide sample codes for making mouse over tag for share icons ? just like the share icons as below link

http://news.cnet.com/8301-13579_3-20037907-37.html?tag=topStories1


I mean , once mouse over the share link , there will be a list of drop down icons for linking other pages, it is only disappeared when pointer moves out of its area . Thanks in advance .