How do I register an "idea", and what does it take to build a website in the size of and similar to facebook?

[l.e.b.]

Hi everyone,

I am a 23 year old who just graduated from college and tried the job market,and I cannot see myself working for somebody else for the rest of my life. I have big dreams and ambitions and I believe I can do better than what I am doing. I have an internet website in mind, something for free.. Basicallly my plan is that people will use it and when it becomes popular, I will have advertisements on it and that's how I will make my money.

I would like to know what it takes (people, resources, money etc) to create a networking website (this is not like facebook but similar in design) Also the website will include a refined search engine that matches keywords..

And my second question is : how do I register my idea so it become mine legally ?