As said before, I'll say again. We are not here to provide you with code, as we are not here to do your work for you. Refer first to the two FAQ's people should read first before posting questions:
CP Q&A FAQ[
^] and
Pete O'Hanlon's[
^] FAQ. We like to help, but we want to see at least a bit of effort on your part first.
As for your question, you create a WebService as you would normally create one, then you call it from Android as you normally call an URL, and consume the response. It's not that hard, once you put yourself to it.