skyscraperpage is an interesting little site, if you happen to be into really tall buildings like i am. it features diagrams and descriptions of the buildings sorted by city, state, country, or even by total size.

birmingham, al [my home town]
washington, dc [ a city i went to once]
new york city, ny [a place i want to go to]
the world's ten tallest buildings
tall historical buildings
buildings under construction