An old saying from the Chinese philosopher and general Sun Tzu could be applied to an alliance between eBay and Google: Keep your friends close and your enemies closer.

eBay and Google, two Internet giants that butt heads when it comes to online commerce, announced a deal Monday that allows the two companies to share revenue on search-related text advertisements delivered on eBay's sites outside of the United States. The two companies will also jointly develop "click to call" ads, which rely on Internet voice technology to connect an advertiser with a consumer.

Financial details of the multiyear agreement were not disclosed, but the companies said they will begin testing ads in early 2007.

Read more about the deal between Google and eBay at CNET News.com.