I've just bought a very useful ebook, The Complete Technical Illustrator by Jon Duff and Greg Maxson and loaded it into my iPad via iTunes, using Stanza as a reader. It's now a perfect companion to any tricky technical drawings that may have me head-scratching.
You can buy and download it by clicking here. It comes in at £15.60 in the UK or $24.00 in the U.S., which is about a quarter or less than the 'real' print edition retail price. Thanks to Technical Illustrators.org for spotting it.