A podcast that I listen to while driving is Mignon Fogarty's Grammar Girl. She makes this stuff fun. I thought her July 15th podcast was terrific in which she gives these three tips for clear and concise writing. (1) Front-load your copy so that the most important information is first or easy to spot. (2) Organize your copy for readers who skim. (3) Cut anything not pulling its weight. You can also print this episode, and if all you do is follow its advice, you're way ahead of the curve.