In addition to the above, not all wireless chargers are created equal. Cheap ones may not work with all phones or may require very precise positioning of the phone (which kills the convenience factor compared to wire). The one that is really good but expensive is TYLT. There is also a cheaper alternative which is supposedly a Chinese copy of Tylt.

I have a Tylt that I am very happy with. I heard that Itian A6 works fine, but I don't have personal experience with it.