The current build of raspbian has the EDIMAX drivers included as standard. However if you are using a distro without these drivers, Robert Savage has a good tutorial on how to use the EDIMAX wifi adapter.Now download the Pushover App, make sure you can send notifications to your pebble (see this entry in the Pushover FAQ for help) and login at http://pushover.net. Create a new application by clicking ‘Register an Application’.
For the code I simplified Adafruit’s tutorial code on playing MP3′s with buttons on the RPi to use only one button and added some code to push messages to the Pushover notification service. All you need to do is copy the code below into a new *.py file on your RPi and replace the ‘application_token’ and ‘user_token’ strings with those from your Pushover Account that you noted down earlier. Also you will need to save an MP3 for playing in the directory with the *.py script. Mine is called ‘doorbell1.mp3′ in the code below, but you can play any file you like.