For those in the market for an emergency charger/battery extender for their Clip, I commend this inexpensive one to you.
It uses 2 AA batteries that fit in the bottom, larger rectangular portion, giving you an idea of the size–just a bit bigger than the 2 batteries. Uses either rechargeable or non-rechargeable batteries. Also has an LED at one end to use, nominally, as a small flashlight. Has a regular-sized USB port, to connect to your Clip with the Clip’s cable.
Available at eBay (a good source) and various electronics sites, including Dealextreme.com, in black or white (try a search on “emergency charger”). With nice pricing, often in the US $2.50-$5 range including shipping (internationally).
Bigger than the small Lenmar battery charger pack, the nice thing with this one is, it can use (and be replaced with) your AA batteries–good for emergencies in a pinch, wherever you are and have spare batteries.