How do I cd to a symlink in PowerShell?

The correct command to link a directory is

cmd /c mklink /D link target

Check out 'mklink /?' for other options.

I recommend using the PowerShell Comuunity Extensions. It adds the commands New-Symlink, New-Junction, New-Hardlink, and Get-ReparsePoint. It also adds some aliases for things like ln so you can just use the Linux syntax.