I have mentioned PowerGUI many times – I especially like the editor. There is a large, and growing, library of PowerGUI powerpacks (additional functionality) available for download from www.powergui.org.
I have just added the PowerShell Help powerpack to my system. Written by Kirk Munro (PowerShell MVP) it gives many views into the PowerShell help system. I may even drop my own help utility in favour of using this. It can be downloaded from http://www.powergui.org/entry.jspa?externalID=801&categoryID=55 – - highly recommended.