This is a photo of a pregnant guppy, with the bulge on her stomach nearing the bottom left, (named gravid spot) where the fry are stored. Pregnant guppies tend to hide in corners on the rocks. In albino guppies you can see the eyes of the fry inside the guppy! As they are live bearing, they don't lay eggs, but have fry strait from their stomach.
This is a guppy fry in a tank, about one week old. Fry are anything from a newborn to three weeks old.
Breeding guppy are easy. They will breed them selves in about 7 - 8 months of being a fry (some way earlier), so they are mature quickly. They are live bearers, so they do not lay eggs but instead they have fry straight from their stomach. They can have about 80 fry per pregnancy (or more), so they might over populate, so if you don't have enough space you might feed a bit to the adults. They can store eggs for a year in there stomachs, while acting normal. If you do not want over population then keep fry with adults and the adults will eat the weak ones. If you do want many fry, then get one of the many fish accessories in pet shops, like breeder tanks, though watch out, some of these stress the female and sometimes even kill the fry. If you see pink drops of matter coming out toward where the gravid spot is, then the female is stressed and having fry prematurely. The only help for this is make the female as calm as you possibly can.
As guppies get prettier and prettier they have a lot less fry then they used to. Some females in older times could have one hundred drops of fry and it would be normal. Nowadays some guppies only 20 drops.