Popup windows dimensions measured with downloaded Caliper:
http://www.iconico.com/caliper/

http://www.att.net - 340x340
http://www.yahoo.com/ - 390x390
http://www.excite.com/ - 450x450
http://www.go.com/ - 550x550

Close the Window(which has displayed four different pages of varying dimensions:

CLOSE THE POPUP - 'http://www.att.net/ - DIMENSIONS: 340x340
CLOSE THE POPUP - http://www.yahoo.com/ - DIMENSIONS: 390x390
CLOSE THE POPUP - http://www.excite.com/ - DIMENSIONS: 450x450
CLOSE THE POPUP - http://www.go.com/ - DIMENSIONS: 550x550