I just spent quite a while trying to get Sencha + PhoneGap to play nice and install the demo app on my Android phone, so here are the installation steps for anyone else unfortunate enough to be as clueless as me when it comes to these things!
1. Download Sencha Touch (http://www.sencha.com/products/touch/) and extract contents to c:\wamp\www\ (or whatever web server you are using's www directory)
2. Download and install Sencha CMD (http://www.sencha.com/products/sencha-cmd/download)
3. Open a command prompt at C:\wamp\www\sencha-touch-2.3.1a-commercial\touch-2.3.1
4. Run "sencha generate app YourAppName ../../YourAppFolder"
5. CD to ../../YourAppFolder
6. Run "sencha phonegap init"
7. Edit YourAppFolder/phonegap.local.properties and change:
8. Connect your android device via USB and enable USB debugging on the device.
9. Run "sencha app build -run native"
10. Done! You should see the demo app running on your device 🙂
Any questions - ask away!