This will allow you to securely create bitcoin addresses using a USB key and print them out.

1. Download Tails https://tails.boum.org/about/index.en.html
2. Boot using Tails USB key
3. Visit http://rpupgy3b5lsyxg43.onion/bitaddress/
4. Verify hashes and PGP keys of bitaddress onion site and Tails.

Less secure but still better than using your own computer:

1. Install https://www.virtualbox.org/
2. Boot Tails ISO using Debian x32 settings

All credit goes to
https://bt.irlbtc.com/view/43496

Send Donations to: 1NiNja1bUmhSoTXozBRBEtR8LeF9TGbZBN (NOT MINE)
http://firstbits.com/1ninja

Signed version of the SHA1 hash of the file:
http://www.bitaddress.org/ninja_bitaddress.org.txt - PGP Public Key
http://www.bitaddress.org/pgpsignedmsg.txt - Signed Message

Theoretically Stephan Thomas or someone else could review the code and provide a signature of the SHA1 hash as well...

Code used from CryptoJS project, Tom Wu's JSBN (refactored), Stephan Thomas bitcoinjs-lib.