Graphical PowerShell V2 CTP2 still looks like a demo, basically speaking. Nevertheless, I find it already suitable for some tasks. Unfortunately it does not implement a few host features including default breakpoint debugger action. Breakpoints without action are simply ignored. Fortunately PowerShell provides a way to solve this. Here it is: simple and yet practically useful Add-Debugger.ps1. The archive also contains Test-Debugger.ps1 to play with and see how debugging goes (in any host, actually). Follow instructions in the script headers.