Hi guys,
I am new to this field, please tell me the difference between telnet and ssh besides that ssh is very much secure in transferring passwords over the network.
Can we remote login from linux to MS windows through ssh?
Can we do the same using telnet?

No idea about windows.

ssh is encrypted, so the data which is sent accross the network is not visible to someone who can intercept the network traffic. The most pointed example of this is then you log into the network - with telnet, anyone who can listen to the network traffic can see your password (e.g. anyone who shares your LAN). With ssh, they cannot see your password.

Moreover, ssh offers lots of funky features which telnet does not. Important among these are public key authentication and port forwarding. RFCs are a good source of further information. Google for "rfc ssh" and "rfc telnet".

So long as you've got an ssh client on the src box and an ssh server listening on the target box, you should be able to login.
Ditto for telnet...
FYI, ssh is port 22, telnet is 23

SSH offers many advanced options as well. My favorite is the use of tunneling. If you modify your config (/etc/ssh/sshd_config) setting GatwayPorts yes you can create encrypted tunnels for other services like VNC for example. I use it as fall back if my primary VPN system should require attention when I am at a remote location.