Memory cards are essential. I would definitely have a 128MB card available in addition to the card you get with the camera.A megapixel is a million pixels, basically points on the screen. If you look at a computer screen very closely, you will see it is composed of dots. Each one is a pixel. You can determine meegapixels by multiplying the height of dots by the width.
My 5MP camera creates approx a 2.5 MB image (depending on quality, etc.). Hence a 128MB card can hold around 60 images. A 256MB card can hold 120, etc. All of the numbers are approximate and depends...
Check out dpreview before making a decision.
Thanks so much for your insights, I will research this with your advice.