I hated that I can't charge the Galaxy Tab 10.1 with USB on computer. I poked around to find out it was the polarity difference causing the problem. I bought this cable and adapter and they work with Galaxy Tab 10.1 and 8.9. Now I can just use my computer USB to charge. One less AC adapter to bring on trip! The cable is retractable making it even better for traveling.
New Trent IMP03B Retractable USB cable
New Trent IMP45B Polarity conversion adapter for Galaxy Tablet
New Trent IMP03B Retractable USB cable
New Trent IMP45B Polarity conversion adapter for Galaxy Tablet