problem in uploading image to server

Can anybody help me out? I want to upload image from my iphone to some server in an application. I tried it with writing NSData using writeToUrl method, but this method did not helped me as this method take file URL as parameter.
I dig out several forums, and found that this can be done by appending NSData in HTTP postdata as explained at link http://discussions.apple.com/thread.jspa?messageID=7820381 . I tried with that also but I stuck on, how to get this image from request (in java).