I personally use Mercurial (Hg) when working on projects with a team.
There is a Tutorial for using Mercurial with NetBeans.
When your team is small you could use bitbucket.org to host your project as it is free and private (but in the free version limited to 5 people per project I think). Otherwise you could easily set up your own hg-server. There are plenty of guides on how to use Mercurial on their website
In case you are not familiar with distributed version controll systems. In a nutshell it works like this:
- When a file is created it gets pushed to the server
- As people make changes to their local copy of that file (or the files) they create changesets which contain only the changes they made.
- Everyone pushes theis changesets to the server from time to time and pulls the changes the others have made. The changesets are then merged to contain everybodys changes.
- The files on your computer are updated according to the changesets you have pulled so that everybodys files are up to date.
This works pretty well as long you don't edit the same lines of code (because then the automatic merging fails because it doesn't know what to keep and what to discard and you have to merge manually) and your files are not in a binary dataformat.
But in your case HTML, PHP and CSS are all text based so you are good to go.
I hope this helped. If you have any questions feel free to ask.
Sorry I could not post more links because my reputation is too low.