Mac OS X: Inklet is a neat piece of software that turns your Mac's multitouch trackpad into a drawing tablet that works surprisingly well.
We generally prefer to stick to the free side of things rather than recommend software that costs a bit of money, but Inklet is an exception for a couple of reasons. First, it's very clever way to use your trackpad as a drawing tablet—and it works very well. Second, at $US25 it's less than half the cost of buying a very basic USB pen tablet. Third, Inklet lets you use it for free with occasional interruptions.
So why is it awesome? It actually works really well as a way to draw/paint digitally with what you've already got. Not only do you not need to spend any additional money, but you don't have to carry around a tablet if you want to draw on the go. If you've watch our digital painting night school lessons and wanted to get started, Inklet is a good alternative to a drawing tablet.
I was a little skeptical at first, so I drew an image for Whitson's feature yesterday to see if it was passable. While Inklet is certainly not going to provide you with the level of detail and room you can achieve with a dedicated drawing tablet, it's absolutely usable. I was able to create a very detailed image. While Inklet lets you draw with your finger, I used a multitouch stylus. If you don't want to buy one, you can always make one the good way or the weird way.
For serious drawing you'll want to invest in a pricier drawing tablet, but if you're just drawing for fun, editing photos, and doing touchups, Inklet is a good way to save some cash and some space in your bag.