I have created a working webservice last week with the help of Google app engine and the google project WSS. Really easy to setup with your existing Gmail-account. I simply created a java bean, generated an xsd from that, created a datastore to store or fetch things and voila, a working service! And the neat thing is that it runs 24/7, so you can use that to service data for your connected mobile app (android or iOS driven, whatever)! For now I use this service to provide the two iOS apps I am working on with an online hiscore table.