check http://processing.org and http://www.openframeworks.cc/ forums, they both have communities full of digital artists and these are mostly the tools of choice for these artists.

London is actually a great hub for this kind of work with artists such as http://ww.chrisoshea.org/, http://toxi.co.uk/, http://www.memo.tv/category/work/, etc based there. I am sure there are local organisations promoting digital work, contacting these people and posting the above mentioned forums might be a good place to start.