'What Charger' depends very much on your budget, you will find numerous threads on this subject. You can buy chargers that would do what you describe from less than $20: http://www.hobbyking.com/hobbyking/s...cessories.html
To about $350: http://www.progressiverc.com/icharger-4010duo.html
And all points inbetween.
The biggest differences between the chargers is the power output and the number of charging ports (plus quality). Power output is not really an issue for you at the moment but if you move on to larger batteries then it's something to think about.
Most chargers need a DC power supply to drive them so you need to pick one of those up too, their prices range just as wide as the chargers themselves. You can pick up some chargers with built in AC to DC power supplies that you can plug direct into the wall, for instance: http://www.hobbyking.com/hobbyking/s..._GENUINE_.html
To hook up your ultra-micro batteries you would need a special lead or board such as: http://www.rcaccessory.com/ultra-mic...ryadapter.aspx