Some of the largest wireless companies in the U.S. have begun allowing ads on their cell phone networks.

It's not yet clear whether U.S. consumers will tolerate cell phone ads, but marketers are intrigued by the idea of it, especially the targeting abilities the platform affords - and cell phone carriers view it as a way to make up for declining revenues from voice calls. So the push is on, according to the Wall Street Journal. For example, Yahoo and go2 Directory Systems are today announcing a deal to put Yahoo-sponsored listings on the go2 Directory local-search site carried by Verizon Wireless, Sprint and Cingular Wireless.

When users go to the go2 Directory to search for local restaurants or movie theaters, Yahoo-sponsored advertisers will show up in their result list. Also, Sprint Nextel and Verizon Wireless have been running trials of banner ads, and Sprint has also been conducting video ad trials.

Some 3-5 percent of phone users click on banner ads on their screens - higher than the 1 percent click rate of computer users, according to Jeff Janer, chief operating officer of Third Screen Media.

The average price for a 4-8-week-long banner ad campaign on a content provider's wireless site is now $75,000 to $150,000, up from $25,000 to $50,000 last year.