If you're not comfortable with using the virtual keyboard in Windows Mobile to take notes, then give SpooNotes a try.
SpooNotes is a free handwriting application that allows you to quickly scribble notes on your Pocket PC using the stylus. You can customize the color and the brush size of your pen, set the background color, and zoom in and out of the note. There's also an 'Auto-expand' tool that enables automatic scrolling when writing close to the edges of the page.
There are a number of useful features in SpooNotes that extend the program beyond just a digital pad for doodling on when you're bored. for instance, you can open an image within the app and draw on it, or even capture a picture from the device camera and scribble on that. There's also an option for sending notes via email, as well as a very useful tool that invokes SpooNotes while you're on a phone call. This could be perfect for taking down a phone number or directions.
Despite these cool features, there are a few niggling quirks that spoil the enjoyment of SpooNotes somewhat. I found the user interface pretty clunky, and it was difficult to figure out what each menu icon actually does. I would've liked to see an eraser tool too. Granted, SpooNotes gives you unlimited Undos, but sometimes you need a little more precision than that. The app proved to be a bit buggy in my tests, and crashed on a couple of occasions, needing a reset. The app is still in Beta stage, so hopefully the bugs will be ironed out once the full release comes.
Once you get used to it though, SpooNotes makes for an interesting new way to record notes on your Pocket PC.