Linux Kiosk

I need a LINUX kiosk that will provide only internet access. It must be able to accept a coin acceptor that will connect to the serial port of the computer. As coins are inserted, a timer will be activated giving the user access to the internet for a specific time. When not in use, a slide show of HTML pages would start (for advertising). A log file must be able to be created to record the number of transactions made, and I must be able to log in from a Remote location to upload new HTML webpages for advertising and to view the log file; maybe using VNC? Your call. Our Browser of choice is Mozilla Firefox. This is an ongoing project with possibilities of more work to update the program as our customer base changes. Thanks and good luck!