Is there any website that will help people create a social networking site?

[excelblue]

This is not a trivial task - you will definitely need to hire some experts for this kind of stuff. I suggest you post an ad on some freelancer sites and see if there is anyone that can do the job. Though, you might be able to save a bit of money by getting some generic social networking software suites instead of getting one custom-made.

Here's what you generally need:
1.) A domain name (eg. example.com) for about $8/yr (often included for free or heavily discounted with web hosting)
2.) Web hosting - a service that makes your site accessible 24/7 on the internet - can run anywhere from $5/mo to $30/mo, depending on the quality of your provider. You will usually not need more than 5GB of HD space or 200GB of bandwidth per month.
3.) Web developer - the expert that will set everything up for you - $300 to $1000

You might want to get something in PHP, Perl, or Ruby instead of ASP.net or ColdFusion. That way, you can use a *NIX host and save on costs. In contrast, ASP.net and ColdFusion are proprietary software and require licensing fees (usually paid by the hosting company and passed on to you).

Other than that, good luck.