[aeden]

What's it written in? If it's in Ruby then Heroku would be my first choice because it's so easy to deploy an app to (with no system setup).

Another option would be to run it on EC2 using a pre-built distro image with the components you need (if you can find such an image). This will be more expensive than Heroku but you can define the stack.

I'm sure others can chime in with their suggestions depending on what you developed it in.