i personally think that u need a server....
a java program that uses ServerSocket and wait for a client which uses Socket to be connected to the Server..
then when the client is connect then u can create a IO Stream from the getInputStream() and getOutStream(), then jus write from client and read from server.....
u can go to my website
http://www.geocities.com/zniter_java/download/FileTransfer/FileTransfer.zip i have a program for filet transfer over a network....
hope it help u......