URBAN Sketchers is a great and very inspiring site. It features the work of numerous artists from all over the world.
Urban Sketchers is exactly what it says on the tin. People who sketch in the urban environment. The main rules are that the drawing should be urban, made at the location, no drawing form photos and no compuer generated images.
So have a look and then get yourself a sketchbook and get drawing.
It’s inspired me to get out there, when I get chance I will be doing just that.