Public-key authentication(Windows)
Difficulty: 4
SSH without a password : Public-key authentication (Windows)
This link will give you some background about public-key authentication, and how to do it with PuTTY:
http://the.earth.li/~sgtatham/putty/0.54/htmldoc/Chapter8.html#8
A few tips:
Use RSA Your authorized keys file is called .ssh/authorized_keys2
Best of luck!
-Evan Miller