The Cult of Mac website has captured some nice shots of the latest Apple Nano ads in Tokyo's underground, in the Shibuya district. The poster has 1:1 iPod nano cutouts all over it, which you can pull off and take home like a "sample". Sleek! See photos here.
From whisky to hot sauce, drive-by insights makes fun of billboards - start here.
By the way, Billboardom.com is a new (Aug 2005) blog dedicated to billboard ads.