In random order of appearance:

The Beacon House Association of San Pedro
http://www.beaconhouseassociation.com/

Feature on LIMA - Leeds Improvised Music Association:
http://www.sandmanmagazine.co.uk/leeds/features/25/impro.html

Alec Finlay
http://www.alecfinlay.com/

Chris Watson
http://www.chriswatson.net/

LIMA - Leeds Improvised Music Association
http://www.limaonline.org.uk/

Benjamin Lylloff - has his freshly new site up and running
http://www.benjaminlylloff.com/

Trevor Wishart
http://www.trevorwishart.co.uk/

Paul Hession
http://www.softdrum.com/

Sonic Stories
http://www.sonicstories.co.uk/

Audun Ellingsen
http://www.audunellingsen.com/

Sphinx
http://www.sphinx-jazz.com/

Paul Kelly
http://www.pkms.pwp.blueyonder.co.uk/

Comfy Chairs
http://uk.geocities.com/comfychair05/

T Taylor
http://www.bayimproviser.com/artistdetail.asp?artist_id=182/

Pinjab
http://www.pinjab.com/

Therese Ulvan
http://www.home.no/thereseulvan/

David Skinner - has temporarily taken down his site, but will be back with new solutions.
http://www.daveskinnerpiano.net/

Matthew Bourne
http://www.matthewbourne.com/

Bjärv
http://www.bjarv.com/

Jonti Picking aka Weebl
http://www.weebls-stuff.com/
http://www.weebl.jolt.co.uk/

Expazz
http://www.expazz.co.uk/

Sawa Teen
http://www.bbc.co.uk/leeds/altogether/world_music/sawateen.shtml/
http://www.saa-uk.org.uk/html/resources/artists/s/sawatween.htm/