They can also have their own domain name such as www.orbital2008.org
The server (a cobalt RaQ4) is mine, and runs about 50 odd sites for fans, businesses, theatres and organisations. I do charge, but not much.
CGI, SSI, ASP, MySQL, PHP, SSH/shell access, multiple users, Front Page Extensions and many other features are all available on request.
For members they can book, amend their booking and use credit cards if wanted.
For the concom there are detailed membership lists, hotel booking summaries, payment records and many things recorded.
Access to features is controlled by concom members capabilities.
Credit card handling is supported. Waveney handle credit cards for our fanzine business and can handle fan conventions through the same account. The software can work with Worldpay or Protx if you have your own credit card account. Other credit card handling companies could be supported if required. We charge 5% for handling credit cards which is pretty much what it costs us.
It is possible to provide the credit card based booking remotely, for conventions that want to manage their own booking, on their own website. The package which is cgi/perl would run on most linux based systems, though would need the support of someone with appropriate system administration skills to set it up. Note that in this case the system is unlikely to be kept up to date with new features.
(The booking system is currently about 5000 lines of perl, sitting on top of my basic shopping suite of 2,500 lines, the full shoping suite is 16,000 lines)
Email addresses such as membership@your-convention.org can be setup that redirect to your membership secretary.
Mailing lists and email through the sites can be archived.
Each member of the committee (and any others they wish to have access) has their own username password. This allows the tracking of who changes what and to control the capabilities.