Today i found an interesting website about Mercurial written by Joel Spolsky. It gives you a brief tutorial about Mercurial and how is it compared to Subversion, another revision control tool widely used in this world. I would recommend this site if you are planning to find a revision control tool to help you working with other people around the world. This tutorial is also helpful if you are having problem with CVS or Subversion and you would like to find an alternatives to it.
Other alternative to Mercurial is Git, originally written by Linus Torvalds (now maintained by Junio). It's also distributed revision control tool, unlike Subversion or CVS which are centralized. You can find the tutorial for Git on Git Book or in Charles Duan's website in Harvard.
Learning how to use revision control will help you organize your team even if your team are not located in the same place, same building, same city, same country. Your team can be widespread around the world, but they can share their work to others without interupting other's work or causing a dillema on the code itself (whether it's a buggy code or late code because people are afraid to commit to the repository unless it has been well tested).