The camera I use for my portraits is the Olympus PEN E-PL5. It's a fantastic little mirrorless DSLR with an articulating viewfinder, which is great for taking self-portraits! As I mentioned in my post on How I Take Self-Portraits, I use my M. Zuiko Digital ED 45mm f1.8 prime lens (prime means that it doesn't zoom). The lens gives a lovely bokeh (where anything in that's not in the focus area is nicely blurred).
I also used a wired or wireless remote control (depending on if my wireless remote's battery is dead. LOL!) and a tripod. I have a black backdrop that I made from PVC pipe and black polar fleece. If you don't have fancy little backdrop you can always buy the fleece from a fabric store and drape it over a door. I used the black backdrop because it creates a higher contrast to the light hitting the face if there's a dark background rather than a light background.
I set my camera to M (manual) mode and set the ISO to 200 (the minimum setting, 100 would be best for the sharpest photos), my f-stop to 1.8 and my shutter speed to 50. You can experiment with your f-stop and shutter speed if you have those settings. DO NOT use your flash, unless you have a wireless flash that can also be used as your light source. I am almost never a fan of non-professional flash setups.
I talk about the edits in Photohop in my Self-Portrait post, which is still the same. You can also increase the contrast if you want more drama in the photos.
That's basically how I created the following low-key portraits. :)