I'll try....
ISO - The "speed" of the film, as it used to be ..... This means that in normal daylight, you can shoot away at ISO 100, and no problems, however if you go into a darker area, you would need flash. If you switch to a higher ISO, for example 1600, you could click away in a low light area without the flash. The downside is you will get more "grain" in the pictures. I like high ISO for taking photos of bands on stage, without ruining the lightshow with a flash. Have a play with it, costs nothing with digital!
F-stop - The amount of light allowed through a lens, i.e. F1.4, lo