Powershell GUI links:

PowerGUI—You’ll find a free edition from http://powergui.org and a professional(commercial) edition from http://quest.com/powershell
PowerGUI is actually at: https://software.dell.com/products/powergui-freeware/

SAPIEN PrimalScript and PrimalForms—Two commercial tools from http://primaltools.com

PowerSE and PowerWF—A free editor and a commercial workflow solution from http://powerwf.com

Idera PowerShell Plus—An editor and console environment from http://idera.com