Comcast is in talks with Microsoft, Yahoo, Google, and AOL to determine which among them will provide search technology and manage online advertising for Comcast's website, according to a source familiar with the process.

Comcast.net now uses Google as its search engine, but the three-year search contract runs through the end of this year, Reuters reports. Comcast late last year began soliciting bids for a two-year search services contract to begin in 2008. Microsoft and Google have already submitted bids, according to the source.

Comcast is also entertaining bids for its first online advertising contract for the website. It has already received bids from Microsoft, Yahoo and AOL, according to the same source.

Comcast.net was the 33rd most-visited website in the United States in terms of unique visitors in February, according to comScore.