I once bought a cheap Chinese set off Ebay that came with wall and car USB chargers and the USB iPod cable and it did not work with my 3G. Last week or the week before I ordered the DLO iPhone car charger off of ThingFling.com for .99 cents and it works great and looks good. They aren't a high-end company but they are name brand and make some decent accessories. I also bought DLO's iPhone portable speakers for $16 off of thingfling and they sound incredible for the price although they don't truly dock...they just use an aux cable.
brad