SSH

SSH A secure shell client

Recommendations
I personally use the ssh product called SSH Secure Shell for workstations v3.2.9. This version was the last version produced by SSH Communications Security made that was free (for non-commerical use). From version 4 onwards they stop making a non-commercial version.

Alternatives
The only decent alternative I have been shown and recommended is PuTTY, which is a free telnet/ssh client. For a free product I think it is very good, but I personally perfer SSH v3.2.9.

At time of writing PuTTY was still in beta.