Community Site

[seahsiyi]

Hi,

Was just wondering what i need to know about building an online community site for people who are at film school / amateur directors.

Basically, i need to know, what do i need to create a website where there could be possibly have 1000 - 10000 users.

Example:
Log in page, user creation/authentication and stuff.
What codes or software do i need to use to make them / how much would it roughly cost to pay someone to do it.

Thanks!

Film Guy