Web Site Messenger Application

No foreign countries Please We need an application that connects to our sql server and allows people to do instant messaging across the web. Very similar to AOL IM or MSN , it doesn’t need all the features as aol or msn, but it does need to allow people to message other users. Currently we have a website with about 5 different categories dating,auction,automotive,real estate and chat. I would like this application to have sound and allow users to change the sound, this application MUST BE USERFRIENDLY(meaning positioning and modifying the window and other items). I would like this application to have groups of users like one for auction and another for dating and so on. There is a security issue for instance, I don’t want the regular users in the dating section to be able to communicate with each other unless they are subscribed user. If they are not a subscribed user then it should send them to a page where they can subscribe. Also this same user if they are communicating with someone in any of the other sections it should be free. I want this application to have a taskbar like aolim and be able to receive messages if the item is just running in the taskbar, with sound and a popup. Also they should be able to send chat room requests and be able to chat in chat rooms. They should be able to add new chatrooms and join chat rooms. This is a low budget application, DO NOT BID if you cannot complete this application; we have been having trouble with other developers not being able to do this application. We also will need all source codes so that we can make modifications in the future, also if you do a good job for the right price you will get to work on this in the future. I would prefer this application created in Visual basic 6.0