A few weeks ago I was looking at presentation notes on adding bio-methane to the domestic gas mix with the fossil fuel natural gas.
http://www.sbgi.org.uk/ContentFiles/UN/Event%20Presentations/Gas%202009/3.%20Janine%20Freeman%20Presentation.pdf
Also, see:
http://www.nationalgrid.com/NR/rdonlyres/9122AEBA-5E50-43CA-81E5-8FD98C2CA4EC/32182/renewablegasWPfinal1.pdf

And recently spotted offer Ecotricity:
http://www.ecotricity.co.uk/news/green-gas-from-ecotricity-is-go!

While I think bio-methane may only make a small contribution it will be interesting to see how develops.

New supplies of Natural Gas from shale gas which has become accessible are pushing down gas prices in the UK due to the world market in LNG.

http://uk.reuters.com/article/idUKGEE5B10ZK20091202
http://nohotair.typepad.co.uk/no_hot_air/can-shale-gas-transform-uk-energy-policy.html

which fits in with what was in the book The Grand Energy Transition by Robert A. Hefner III mentioned in previous energy post.

And others:
http://theenergycollective.com/Podcasts/43813