from Wikipedia:
also: Lithium-ion polymer batteries, polymer lithium ion, Li-poly, Li-Pol, LiPo, LIP, PLI or LiP

Rechargeable batteries which have technologically evolved from lithium-ion batteries. Ultimately, the lithium-salt electrolyte is not held in an organic solvent as in the lithium-ion design, but in a solid polymer composite such as polyethylene oxide or polyacrylonitrile. The advantages of Li-poly over the lithium-ion design include lower cost manufacturing and being more robust to physical damage. Lithium-ion polymer batteries started appearing in consumer electronics around 1996.

fullriver 401218HS20C, fullriver 452026HS10C 

USB LiPo charger from sparkfun >> http://www.sparkfun.com/commerce/product_info.php?products_id=726

Full River is one of the pruducer of Lithium Polymer Batteries. You can find it in many online shops for model making and micro electronics.

Tenergy is also a Lithium Polymer battery producer.

Lithium-ion batteries can rupture, ignite, or explode when exposed to high temperature environments e.g. in an area that is prone to prolonged direct sunlight. Short-circuiting a Li-ion battery can cause it to ignite or explode and any attempt to open or modify the casing or circuitry is dangerous.  

You need a charger and balancer (it is also called Protection Circuit Module) for Lithium Polymer Batteries to prevent over charge or over discharge. You can buy a LiPo battery with PCB already connected, or already assembled PCB. There are many online shops that sells such product. Here is some example.

http://www.all-battery.com/li-polyersinglecells.aspx

http://www.all-battery.com/protectioncircuitmodulepcbfor37vli-polymerbattery85alimit-pcb1s.aspx

Or, you can build your own PCB and attache it to LiPo batteries. Here is a schematic of PCM that usis LTC4058 component. (thanks to Simon from V2)

>> PDF is Here