This has actually been around since July 2004. I presume it has not
been that widely publicised to enable early problems to be ironed out,
and to prevent it gaining an unfair reputation for inaccuacy.

See http://www.transportdirect.gov.uk/programme/portal.htm

I used this recently to find out about bus services in Norwich. The
information it gave me was most helpful, and accurate apart from
ommiting to mention that the bus I wanted actually stopped closer to
the station (on the railway station forecourt as opposed to a bit
further out of the station on the main road).

I got the critical info I was after - the bus routes and route
destination so I could ensure I was headed the right way, plus the
frequency of the route and a map with a name of the locale of the stop
where I wanted to get off - which meant I did get off at the right
place and I was able to ask for the right fare (fare info was not on
the website but, for this journey at least, it wasn't important).