Well all very good questions.. there are many ways to do this. Some are easy and some are hard. The easiest thing you could possibly do is set up a page at a site like this or myspace or face book or something. You could even buy your.com name and use it on that page. This would be best for somebody that doesn't have much web design experience and wants to get started quickly and inexpensively.
You can go to a site like godaddy.com and buy your .com pretty cheap. Make sure to pay the little bit extra to make it a private registration. That way nobody knows your real name.
You can get an account set up from paypal to accept money for cam shows for free. Don't set it up on your page. Do it discreetly as paypal does not favor adult business. You can have money sent straight to your bank account via email from your customers and the only take something like 2-3% to use it.
You can advertise on your site that you do shows with yahoo or msn or whatever instant messenger you use that allows the use of your web cam.
Things to put on your page.. you can put photos or video clips and write about yourself. Also make sure to include a few ways for guys to contact you. The biggest thing you want to be sure of when you are working for yourself is that you get yourself out there and promote like hell. You can make much more money working for yoruself but you have to do a whole bunch of self promotion.
This is what I recommend you do.. set up a page like this.. http://www.camgirlindex.com/blogs/jessica080806/ (my blog page here in the community) and post to it very often. You can post whatever you want and as long as every post is an original it will help you get indexed in the search engines for free so that you can be found that way.The more frequently you post the higher up in the search engines you will be and the more clients you can get.
I also know a whole lot about web design if you have any more questions. I hope this helps. The key to big money is self promotion which is what this site is all about. You have come to the right place. Have a great night! 