Thanks everyone for the replies.
Dubbya - I agree Google is well in front with local search, thanks for the info.
Deepsand - "Drivel" may have been a bit harsh - but I thought it was daft that Yahoo would direct you to Infoserve to enquire about a local listing only for Infoserve to phone you to say that they effectively had no control over them..
Addlocal - In the UK at least (and I assume other countries) - the Google local information comes from the Google local business centre - which you sign up to and then Google send you out a physical postcard so you can confirm your address etc....
NB - in case anyone is interested
here is a related thread on how to improve your Google Local ranking...