- http://www.BitAddress.org

if you don't want to trust that your computer is secure then here's an even more secure approach:

Copy the HTML from BitAddress to a thumb drive.

Boot from a liveOS (e.g., boot to an Ubuntu distribution image)

Brian Krebs gives an example of doing this for online banking here:
 - http://krebsonsecurity.com/2012/07/banking-on-a-live-cd/

Open the HTML from the thumb drive. 

Print.