When you use the Get-Credential cmdlet, you get a GUI dialog box to enter the credentials.  This is the “Common Criteria Certified” way of handling credentials.  It is also a pain in the butt at times.  If you are an admin, you can alter this and request credentials via the command line as follows:

PS> $key = “HKLM:\SOFTWARE\Microsoft\PowerShell\1\ShellIds”
PS> Set-ItemProperty $key ConsolePrompting True
PS> Get-Credential

cmdlet Get-Credential at command pipeline position 1
Supply values for the following parameters:
Credential
User: ntdev\jsnover
Password for user ntdev\jsnover: **************