You've got plenty of megapixels... don't worry about that. Here are some other tips for photos of children:

• use props: kids love to play with toys, balls, chairs, tables, etc. In addition to helping to occupy their attention you can add an interesting visual element to the photo.
• shoot from their eye level. Far too many photos that parents take have the "6 foot guy with a camera to his eye" look.
• realize that your subjects have a short attention span. You won't be able to keep a young kid interested for very long.
• I can't think of any lighting considerations that will be specific to children... indoors or outside, standard lighting suggestions are in effect.
• when photographing children playing outdoors, think about how you'll handle motion as they're running around. Are you going to try to use a fast shutter speed and freeze the action? Do you want a shallow depth of field to keep the background out of focus? Might you intentionally use a slower shutter speed to show the motion? What about panning?

Have fun taking photos of your kids... experiment and find what creates effects that you like.