Q:

xtify with a webservice

is there any tutorial for Xtify notifications with the android, to get information from a webservice into an xml file?

A:

I'm not exactly sure what "get information from a webservice into an xml file" means however Xtify's documentation is quite extensive.
Check out Implementation Guide Android for details on how to get started.  I also highly recommend downloading the SDK which includes several sample Android apps which you can use as a guide.
There are couple of API's available:

Notification Configuration API
Push Notification API

