I strongly recommend Flash based chat apps over PHP/MySQL/Ajax based ones due to the amount of bandwidth and server resources that are required to use them compared to Flash. Here are a few worth looking into (along with the odd tutorial and $5 app): http://www.userplane.com http://www.tufat.com/script39.htm http://www.dmxzone.com/ShowDetail.asp?NewsId=8210 http://www.chat-one.com/LiveChatCategories.aspx