You can use VSCmdShell to run a PowerShell script from within Visual Studio 2008.
After installing VSCmdShell you can change the startup folder (working folder) of the powershell window:
- Tools > Options > Power Toys > VSCmdShell
- Set Shell Selection: Windows PowerShell
- Set Solution Root Directory as Starting Directory
To show the powershell command prompt in Visual Studio 2008 click View > Shell Window (VSCmdShell)
To run a Test.ps1 PowerShell script, added to the Solution Items you can type .\Test.ps1