To compete with Adsense, Yahoo is finally ready to launch their own network. It could be as soon as Wednesday if Cnet is correct.

Yahoo is planning to launch on Wednesday an ad network for small Web publishers intended to strengthen its hand against rival Google, a source familiar with the plan told CNET News.com.

As previously reported, the Sunnyvale, Calif.-based company has been working for months on a self-serve advertising service tailored to bloggers and other small Web publishers, a move that homes in on Google’s territory.

While Yahoo and Google already go head-to-head serving major search-advertising partners such as America Online, Google has largely enjoyed a monopoly delivering its signature text-only ads to smaller content sites, including blogs.

Now Yahoo will play to that constituency and challenge Google’s pricing power in one of the fastest-growing online mediums: blogging. Like Google’s service, Yahoo’s self-serve product will display text ads deemed relevant to the content of specific Web pages. Advertisers pay only when a reader clicks on their ads. Yahoo and publishers will split the fees.