In a launch almost unmentioned at the end of last month, Yell (a UK equivalent to SuperPages) has launched its own PPC advertising solution. According to a discussion on WebmasterWorld, Yell is using the backend of European search portal (and PPC network) Mirago.
The service will allow UK businesses to buy targeted advertising space on search terms such as "plumber" and "bookshop in Bristol" from 20p (around $0.40) per click. The UK Yellow Pages and Yell brands have been seen in the past as very reluctant to adopt new advertising models, with most of their online inventory being sold to existing offline clients in addition to ad space in the Yellow Pages dead-tree directory.
WMW members have not looked favourably upon this launch, criticising issues with Mirago's ad-serving system and the relatively high minimum cost per click set by Yell.
Competitor (both offline and online) Thomson Local have had a PPC solution for a few years now under the name of Web Finder, publishing ads on behalf of businesses on their own local listing directory as well as other partner networks. I beleive that they have had problems matching the conversion rates of major networks such as Google though, even for more home-turf searches such as for plumbing products.
I personally feel that Yell still has tremendous potential, even though it is several years late into the PPC market. Yellow Pages is a very strong brand in the UK and can reach a less internet savvy audience that other networks have yet to corner. It may be optimistic to state that they will dominate the UK local search market, although their strong brand and accurate human-moderated source of business data is a massive asset that could give them a large chunk in this developing area of search - as long as they get it right!
Further Discussion at WebmasterWorld.