Go to www.rcgroups.com
and read about lipos there. From my other hobby flying electric model helicopters, it's very important to respect lipos unless you want your bike, shed, car or house to end up in flames.
In a nutshell, lipos can explode or catch fires if you over charge them. If cells go over a certain voltage (3.5v IIRC) then you have a serious problem. So cells are carefully matched to so that they charge and discharge at the same rate.
Then a Lipo charger is a bit different to a Nicad charger, which just increases voltage until a maximum charge current is reached (constant current). Instead the Lipo charger charges in two steps: it increases voltage until a specified current is reached (constant current), then when the battery pack peak voltage is reached the current reduces to complete the charge (constant voltage). The peak voltage is also calibrated to <0.01v. So that's why it's a very bad idea to attempt to charge a Lipo cell with a nicad charger. BOOM!
Now the battery charger can only 'see' the whole pack voltage, so if you have 2 cells in series, you could just charge each cell individually to ensure voltages are all fine. But that's difficult and requires two chargers. So instead balancer circuits monitor pack voltages and just pass a tiny current to keep all cells at the same voltage. This is particularly important on model helicopters where you might run a 16-cell 8s2p pack for example. The balancer is typically part of the charger in RC applications and part of the cells in consumer applications.
The other thing to watch out for is that Lipo cells have very low internal resistance, so a small Lipo pack can output all its charge in about a second, giving a similar effect as shorting out a lead acid truck battery. So when you put connectors on the bare cells you need to avoid shorting the wires. For example if you happen to short out the cells by touching wires with a wedding ring, the ring will glow red, the wires will weld to the ring and you will probably lose your finger.