You can certainly run them in series. All you do is connect cells + to -, + to - until you get the voltage you want/need. There are chargers on the market that are capable of charging up to 9 LiPoly cells in series.

Parallel is simpler. You connect multiple, IDENTICAL packs together, + to +, and - to -. The packs have to have the same type and number of cells connected in series.

There's lots more info available in these forums. Take a look around.