BusinessWeek has an interesting story on mobile advertising in the UK:

Banner advertising on cell phones is reaching its target, especially female heads of households, according to the retailer's mobile arm
...
The mobile virtual network operator has been trialling a WAP advertising portal since May 2007, which Tesco said has displayed strong month-on-month growth, gaining 300,000 unique visitors in December.

Banner advertising served up on the portal delivered a click-through rate to tailored WAP campaign sites of between three and seven per cent, said Tesco. Brands advertising on the portal included Bee Movie, ITV, Nivea and Teletext.

Read more at BusinessWeek.