There are many iPad styluses out there, but most of them suck. And the ones that are good lack something extremely important for amateur and professional artists alike: pressure sensitiveness. Fortunately, the Jot Touch will be here soon to fix this.
The Jot Touch by Adonit uses a transparent ballpoint disc to mimic the tip of your finger. It's capable of sending pressure information to the iPad using a Bluetooth connection, and it has two buttons that allow you to quickly switch between tools.
Since it needs to talk to the app itself, developers need to enable support for this stylus. As a result, there aren't many Jot Touch-ready apps at the moment. In fact, there are only three, including Procreate for artists, and Clibe for those who like to keep free-form journals. But there's no support for Autodesk's Sketchbook Pro. Hopefully, more will come out soon.
It's not clear how well the Jot Touch performs. It looks like it lags a bit in this video demonstration, but that may be an effect of the glass (I've seen this in videos I've made on the Wacom Cintiqs -- there's no real lag in real life). I will be testing one soon and will let you know what it's really like to use. [Jot Touch]