Instant Message Widget Self-hosted

We would like to have an open source instant message code that will be hosted on our LAMP stack. The IM code cannot be part of an outside service. We are looking for a freelancer with experience in setting up instant messaging to install and maintain this code. The IM widget needs to permit: one-on-one and group IM from a list of users we provide, set an online/away message, mute IMs, expand and minimize window, and have a new message indicator. When applying, please let us know of your experience installing IM, what open source you would use, questions/concerns you have, how long you think it will take and when you think you could start.