Google will provide web search advertising for eBay in all markets except the US, according to the terms of a new deal that also sees the two working together on “click-to-call” ads.

Although eBay relies on Yahoo to supply ads in the US, worldwide Google has become the preferred partner.

The new “click-to-call” advertising scheme will use instant messenger and Skype to connect advertisers with potential buyers for realtime web chats or talking over VoIP.

It is hoped this will aid advertisers who don’t have a website and rely mostly on telephone directories for people to find them.

The deal ties the two companies closer together, with eBay also planning to offer Skype users the option to download the free Google Toolbar.

The deal with eBay is part of a push by Google to expand its advertising business, having also signed agreements to supply ads to MySpace, and to test an ad-supported video syndication system with MTV.

In related news, Google announced it was expanding into the business software market and would release a set of Web programs for email, calendar, and communications.