Let them e. just feed them and maintain them. Also the WorldWideWeb has tons of information.
Why mention the WWW if he is already on a fishkeeping site looking for advice?.....Most of the feeder guppies that are sold around here include lots and lots of plump females but I'm not sure if what they are carrying are fertilized at that point though.You could place a few females in another tank untill they give birth and then remove the adults afterward.