Create Remote App.

I need someone to create a Remote Application that can be used on Mac os X, Windows, and linux. You can make 3 different apps. There are MANY MANY remote apps open to open source scripts but i need to own the app because i will be reselling. I have a programmer finishing up the Java applet that these remote apps will be running in that the apps need ot work with. the apps should 1) be easy to set up from any computer so that anyone can do it. It should be a) Download, Select Username and Password one machine b) go to other machine and sign in c) use Remote machine