146024 Windows / Mac Chat Client

We currently have a web based chat software app for people to chat to web site visitors - we would like a chat administration application developed for BOTH Windows (.exe) and Mac (.dmg) with the following functionality: a) Check for incoming chat (every 15 seconds) b) Answer Chat Requests c) View History of Chat Requests d) End a Chat d) Settings (each staff will have a username and password) The application should work in the taskbar (minimized) on Windows and should also work in the Dock on the Macintosh, and provide a visual/sound alert of new chat requests and new chat messages. The chat protocol uses HTTP for exchange of messages between our chat software on the server and the desktop client. All chat handling done through single script /[login to view URL] with different CGI parameters. Requests can be done with POST or GET HTTP methods. Every successfull request to [login to view URL] returns single complex JSON object.