PuTTY is a free implementation of Telnet and SSH for Win32 platforms, written and maintained primarily by Simon Tatham.
The latest version is beta 0.49.
LEGAL WARNING: Use of PuTTY and PSCP is illegal in countries where encryption is outlawed. I believe it is legal to use PuTTY and PSCP in England and many other countries, but I am not a lawyer and so if in doubt you should seek legal advice before downloading it.
Use of the Telnet-only binary (PuTTYtel) is unrestricted by any cryptography laws.