First, you need to research the idea and make sure that someone else hasn't already beaten you to it. Good ideas are in the air - many people come up with similar ones at the same time. At the very least do a number of Google searches with words and combinations of words that express your idea. Investigate any matches.

If your idea still seems original, then you can explore the abstracts of existing patents on the Internet as well. This takes more time to get through, but is well worth your time. You could of course spend money on a lawyer, but I'm assuming that's not an option.

If you haven't seen anything like your idea, You could file a provisional patent through Legal Zoom, but you'd need to create the patent document. You could also use a lawyer to do this, but it gets rather expensive.

You could also chuck all of the patent talk out the window and simply build a prototype. Find friends with web design skills who would be willing to work for a share of the product or company. You'd be surprised how many people are willing to do this if they're sold on the idea.

Once you have a prototype - or even better, a working Beta site - you can then put it out there and see if anyone is interested. Mark Zuckerberg did this with Facebook, and look what happened!

Good luck.