It might be useful to look at Axis as well as be aware of the ongoing debate on public art
http://www.axisweb.org/dlForum.aspx?ESSAYID=18014

Those of you thinking about accessing new audiences by putting work into public spaces could contextualise the process by referring to a Guardian article on the recession.
http://www.guardian.co.uk/artanddesign/2009/feb/18/slack-space-vacant-shops

Public art online has some very useful information. Sample the link below for a downloadable research document on Millennium Square, Leeds.
http://www.publicartonline.org.uk/resources/research/mill_square_leeds.php