Upload/post file to asp server without a form, from a android client application

I am working on an application on android using eclipse, where my application upload certain files to server, (of course with user permissions), 
but On server, i want to receive the file and put it under some directory, without opening a web page and click on submit/upload button, btw server is iis 7, default of windows.

i have been going through many google links before posting here, so if you know any working tutorial, or some hints or code snippet for any webapi or whetever, it would be great.