The Installation of PhoneGap is pretty simple and infact its just about copying the files to the Visual Studio template folder to kick start your Windows Phone Development using PhoneGap .
One of the Prerequisite to install the PhoneGap is the Operating System . PhoneGap requires Windows 7 or Windows Vista Service Pack 2 . Note that installing Windows Phone SDK itself requires pne of the above :)
Also make sure that you install the Windows Phone 7.1 SDK which can be downloaded from Create.msdn.com
If you have the above things ready , follow the below steps to get started with PhoneGap
1. Download PhoneGap 1.3 here
2. The downloaded file is a zip file which contains the necessary templates for developing Windows Phone App using PhoneGap for Visual Studio 2010 .
Copy the file and extract it to the Visual Studio c# template folder . This is usually
C:\Users\<USER NAME>\Documents\Visual Studio 2010\Templates\ProjectTemplates\Visual C#
3. Start Visual Studio 2010 and create a new project . In the list of available templates , you should see the Phone templates with the name "PhoneGapCustom" and "PhoneGapStarter" .
Select "PhoneGapStarter" and rename the project as per your need and click ok
4. The Visual Studio Solution will contain the folder "www" and "GapLib" and few other important files .
The GapLib contains the Windows Phone 7 PhoneGap Class library dll where as the www folder contains the HTML and CSS file .
5. Double click on the index.html file inside the www folder and edit the HTML file as per your needs .
6. Press F5 to run our first PhoneGap Windows Phone App on Windows Phone Emulator :)