Geonames has many high quality services listed here: http://www.geonames.org/export/ws-overview.html

List cities in boundingbox (press cities button):
http://bbox.me/bbox.html?id=70

List placename at center (press placename button):
http://bbox.me/bbox.html?id=71

List weather at center:
http://bbox.me/bbox.html?id=72 (press weather)

And lastely the coolest. Throw a boundingbox at wikipedia and return the articles (press wiki.me):

http://bbox.me/bbox.html?id=73 (press wiki.me)