Clone of IP Messenger

Hi, I am looking at creating a small piece of software for use on Windows and Mac based computers. This would be a small inter-office IP based communication tool. It should have following features... 1. Users should be able to see a list of other users that have it running. It should not need a server (dont want a client-server model). People can run it on their machines and it should see list of other users. 2. Apart from a regular one to one chat, a multi-cast option. 3. File sending and receiving. This is a very simple application and we would provide with the interface and skins. You just need to create the backend. In fact you can use many publicly available source codes for instant messengers. Time is really critical. We need it delivered in 7 days from acceptance. Reference: IP Messenger - [login to view URL] This link also has a source code. I dont mind if you download this source code and customize it for us.