The easiest method is to create a new file association that executes wperl.exe
To change which program starts when you double-click a file, follow these steps:
Click Start, and then click Control Panel
Click File Types tab in Folder Options window and the full file types and their association will be listed
Click New and type the File Extension (.wp) in the box and then click Advanced
Choose an association for the file type (wperl.exe)
Click OK and then Click Close
Here is the original Microsoft KB article
