Android : File Transfer android

I'm working on an android application that founds all the devices connected to the same network via WiFi, now i want to send files from my android application, the receiver device may be an android device or anything else(windows or mac etc). I'm new to android programming and i don't know how it will be done, only i want to do is to send and receive files from my application, Is it possible if yes then how?? Thanks in advance and sorry for poor english