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The bq2404x series of devices are highly integrated Li-ion linear chargers devices targeted at space-limited portable applications. The devices operate from either a USB port or AC adapter. The high input voltage range with input overvoltage protection supports low-cost unregulated adapters. 

BQ24040: Single Cell Li-Ion Battery Charger With Auto Start  - [Link]

This is a universal charger of Lithium Ion batteries based on Atmega8 microcontroller. As you may know, LiIon batteries have many advantages comparing to regular NiMh or NiCd. Main of them are: high capacity by weigh and volume, no memory effect, fast charge and so on. But these batteries require special charging algorithm. You cant plug to some voltage and expect them to charge. It needs non constant voltage and current during charging cycle. Charging generally follows these steps:

• Current control at the Max Charge Current is used until the battery voltage reaches the voltage threshold (normally 4.1 or 4.2 volts per series cell). The battery is about 70% charged at this point;
• The voltage is now controlled very accurately (this is very important) at the threshold voltage while the current drops off naturally. Once the current reaches the lower cutoff ( about 100 mA per parallel cell typically), charging is stopped after a top-off time delay.

Lithium ion battery charger for robotics - [Link]

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Lithium batteries seem to be everywhere these days. We can find them in our cellphones, laptops, portable media players and etc. We all want to make our batteries last as long as possible, but some well intentioned advice from friends, could be harming your Lithium battery’s life span.

4 Tips to Extend Your Lithium Battery Life - [Link]

This is a charger for lithium ion batteries which takes its power from the USB port of a computer. It uses the MCP73861 or MCP73863 Li-ion battery charger chip manufactured by Microchip. The circuit board is a piece of single sided copper clad board. A hole is cut inside it so that it will accommodate the integrated circuit.

The MCP73861 or MCP73863 (they are similiar, with only slight differences which do not affect the circuit connections) is available in a small leadless package.

The difficulty? There are no leads to solder to. The advantage? There are no leads to break!

USB Li-ion battery charger - [Link]