Revision control is good!
That way I won't end up with six different projects built into one source file. Like sphereGen, that didn't actually have anything to do with spheres for the better part of three months. So the first step to getting started with Mercurial or any for of revision control is to figure out your motivation for doing it. Now that you're motivated we move to phase two.
Getting Mercurial installed
I'm going to instead reference the Mercurial page for the moment and skim right by the bit where we just have to wait for the sysadmin to do it in the cs labs and refer the interested reader to the Mercurial website the installation stuff is pretty easy. Try it on your own machine!
Learning the basics
There are a lot of great references out there for Mercurial. I'm working my way through their tutorial, and if you are interested in snagging a little bit of server real estate for your projects you can go to a site like Bitbucket or GitHub and set up an account. Who knows, maybe we'll get really organized and set up our own repository on Arthur. There are links to the goods below in the Helpful Resources section.
Write awesome stuff. Go. Do. Post.
There is a graphic interface available for all you Windows people TortoiseHG. I'm not sold on it, and I found it a bit cumbersome, so I will probably not say anything else about it. If you want to use it, and find it useful, that is great.
If you want to take a gander at my public repositories you can find them here. There isn't really anything there yet, but I'm working on it.
I've also played a bit with the built in serving capabilities of Mercurial all by its lonesome. Its a pretty useful tool on the Sewanee network, but I'm getting the feeling that it isn't a very good long term solution. Mostly its just made it easier to work between the machines sitting on my desk. However as soon as I get my security settings configured the way I want I'll post a better diagnosis.
This is a partial list of the materials I have been working through. Some of them are quick reference sheets that I haven't made up my mind about. It will probably take a bit of time for me to decide to endorse any of them.