Here are some links to information on Raval. Lots of good stuff here!
Short and sweet entry in Wikipedia
A bit more information here and quite a good reference site for Barcelona in general
The top 10 tourist things to do in Raval, most of these are excellent recommendations.
The official tourism site of Barcelona.
A great site (some of it is restricted) using Raval as a case study in urban renewal. Well worth spending some time if you are interested in the extent of the changes made to the area.
Another broad write up of the area.
