http://www.ualberta.ca/CNS/RESEARCH/LinuxClusters/pka-putty.html
http://www.dailyiteration.com/howto-passwordless-ssh-authentication-with-putty/
http://blog.shvetsov.com/2010/03/making-pageant-automatically-load-keys.html+
Note that in order for SSH authentication to work, you often need to set your .ssh folder and authorized_keys file permissions to specific values. Here are settings that I used that worked:
drwx------ 2 ayahya ayahya 4096 Jul 13 14:23 .ssh -rw-r--r-- 1 ayahya ayahya 875 Jul 13 14:23 authorized_keys
Your private keys should always NOT be readable/writable by anyone but you
-rw------- 1 ayahya ayahya 951 Jul 17 14:00 id_rsa