What is the best way to set up a system that checks for events daily and sends messages via email, Twitter, SMS, and possibly Facebook? Keep in mind, that I do not have access to a web server with root access (Using Rackspace Cloud). Would PHP have a solution for this? Would there be any drawbacks to using Google App Engine and Python?
If you are using Google App Engine with Python you could use "Cron" to schedule a task to automatically run each day.
GAE also allows you to send emails, just a little tip: make sure that you 'invite' the email address used to send mail to the application as an administrator so that you can programatically send emails etc.
Check for Event Daily, and Send Notification Messages