Where did Telnet Go in Windows Vista?
Go to Control Panel.
Go to Programs.
Go to Program and Features.
Click Turn Windows Feature on or off.
Check mark the telnet client.
Windows Telnet Clients prefTelnet
The following setups have been created for Windows, making installation and use much easier.

Telnet protocol handler is no longer supported in Internet Explorer 7+ this registry file fixes this issue
* SyncTERM for Windows with installer [download from support site] SyncTerm great multi-platform telnet client (Win/Lin/BSD/OSX).
* mTelnet [download from support site] is a great console based telnet application. This installer has the Windows Console color fix built in. 
Downloads
downloads
Windows Console Fixes
[download] WindowsXP/2000/NT Console Prompt Ansi Color FIX!

Telnet BBS Clients for linux
[download] SyncTerm great multi-platform telnet client (Win/Lin/BSD/OSX).
[download] Termix is a kickass linux client for BBSing.

Other Telnet BBS Clients
[download] RipTerm 1.54 - Preconfigured for Windows
[download] NetRunner 0.081 - Windows Ansi Telnet Client
[download] QModem Pro for Windows - Ansi/RIP Telnet/Dialup Client with CRACK
[download] RipTel 3.1 - Windows Ansi/RIP Telnet Client with CRACK