If you are worried about the 'sweet spot' then one like mine might be in order:
http://www.amazon.com/Panasonic-QE-TM101-K-Black-Wireless-Charger/dp/B0051R4ECM
Not easy to find any more, and only ever sold in Japan originally, but it moves the charging coil to the phone, so you just slap it down and walk away.