Where do I start..and then what do I do?

I have an idea for a web-based business. It’s along the lines of a business link site and I’ve found nothing like it so far in all my searches. So… I’ve got the name picked out – checked it out and it’s not being used. Where do I go from here?I know that somewhere along the line I’ll need to a) register the name (where? how?) b)design the web site (duh!) c) sell the idea (I’ve got that covered) d)launch the site (not quite sure about that one either) e) advertise (I’ve got the idea on that one too)
So, mostly, I need to know how and when to get my name and do I get a normal biz license thru the city? What else? Any advice? thanks!