Another great Make: Online video by Collin Cunningham.
Fingertip input is great for most touchscreen usage like typing, web-browsing -- all sorts of virtual button-pushing tasks. But for many people, drawing remains an activity best approached with a pen, pencil, brush, etc.
With a bit of conductive foam and wire, it's surprisingly easy to make your own conductive stylus, suitable for use with iPhone, iPad and similar capacitive touchscreen devices - and you'll likely find it a lot more precise compared to regular fingertip input.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects