Urban Airship has a similar service (even priced similarly): http://urbanairship.com/ Their focus is specifically mobile apps, & they have nice sample code for iPhone/Android/Blackberry. Gets spendy faster than Amazon, but I've used it for personal stuff and it's really easy.

Ex.: I do a lot of database work recently, so when I kick off a 90min query, at the end I ping them with some JSON and my phone meows. (Meow! Stop drinking! Your query is done!)