One of the reoccuring question I hear is "Where can I get good but inexpensive aftermarket batteries for my digital camera". The only place I've used for aftermarket batteries is SterlingTek. They were reccomended by serveral folk on the Canon 10D & Digital-Rebels list. I've purchased battries for a Canon 10D, 30D, Rebel XT and Canon S70 as well as a recharger for Canon BP511 batteries. The charger plugs into a regular household outlet AND also comes with a cord to plug the charger into a car cigarette lighter.
The batteries have all worked perfectly and I would reccommend SterlingTek as source for all of your camera batteries. Their shipping is fast and customer support is the best.
If you have another source for inexpensive batteries and chargers for digital cameras, I'd love to hear about them.