Once Tablet PC option is enabled, go to Start Menu and search for note or notes, and you have access to Sticky Notes application!
You can find it All Programs >> Accessories >> Tablet PC >> Sticky Notes.
This Sticky Notes does not have a very impressive appearance - black font color on yellow background color. Background/foreground color change option is not available. UI is very much non-Vista. However, it allows you to scribble your notes, and record your notes
If you search for Tablet, you will find another hidden app - Windows Journal!
It has a very book like appearance, and you can add images as well. And you can change the background and font color. And multiple pages. And option to save the Journal entries.
When you first run Windows Journal, it gives you option to install Journal Note Print Driver.