Display a MessageBox from PowerShell

[System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms") | Out-Null
[System.Windows.Forms.MessageBox]::Show("Hello there !")
[System.Windows.Forms.MessageBox]::Show("Hello there !", "Some title")


you can also have buttons like:

0: OK
1: OK Cancel
2: Abort Retry Ignore
3: Yes No Cancel
4: Yes No
5: Retry Cancel

[System.Windows.Forms.MessageBox]::Show("Hello there !", "Some title", 4)

you can olso read the unswer from the user:

$Unswer = [System.Windows.Forms.MessageBox]::Show("Hello there !", "Some title", 4)
if ($Unswer -eq "YES" ) { # perform sone task }
else { # perform some other task}

more info on msdn