PuTTY is a client program for the SSH, Telnet and Rlogin network protocols.
its help to access remote servers like Linux unix using SSH. and telnet feture will help you to access routers and other ssh/telnet clients. Putty allso support SSH2. it is a better replacement for windows hyper terminal. Putty is must tool for a IT professionals. Try PuTTy.
You can download putty from http://www.putty.nl/download.html
I recommend putty connection manager (Putty Cm) for the expert users.