Are you hosting this yourself or are you having someone else host it? If you are having someone else host it, what technologies do they support? If you will host it yourself, you need to decide upon which technology you want this to be based on (the two most popular being PHP and ASP). then you need to decide upon a database server (Microsofts SQL and MySQL come to mind).
OK, once you've settled on your technology, I'd start with the system requirements. Having a form for someone to make selections on is one thing, but what happens to the data once they submit it. Does it get email to someone, does someone log into a admin site to verify/confirm the reservations. Are you wanting these reservations to feed into another system? Etc., etc.
Then you need to designing the database. If you've never designed or worked with databases before I can't really explain what you need to know in a forum post. Do some googleing or pick up a book.
As for the actual coding, if you have ever programmed before then you should be able to pick up pretty quicking using some reference sites for PHP or ASP. If not, you either need to find some beginner tutorials or get a book on the language you will use. If you know JavaScript fairly well, then PHP will be VERY easy to pick up - the biggest difference being that you will need to learn about database interaction.
Here is a tutorial on creating a login for PHP that I used to get started with PHP. However, I had some experience with programming and databases beforehand, so that helped.
Going forward, do what you can and if you get stuck ask specific questions in this forum. There just isn't enough space to fully answer a question such as this. Good luck.
Michael J
