PowerGUI is the PowerShell editor that I currently used.
As quoted from the website, PowerGUI is an extensible graphical administrative console for managing systems based on Windows PowerShell. These include Windows OS (XP, 2003, Vista), Exchange 2007, Operations Manager 2007 and other new systems from Microsoft. The tool allows to use the rich capabilities of Windows PowerShell in a familiar and intuitive GUI console.
If anyone has better IDE which is free, do let me know.