ifitwasmyhome.com is a little google maps mashup that lets you visualize the bp oil spill by superimposing it on your current location.
these things are always tricky to visualise, for lack of reference points, but this map shows a very concrete term of comparison: slovenia. the whole of slovenia is engulfed in that stain (plus big chunks of italy, austria and croatia).
for us living here, and exploring this country, it surely puts things in perspective.