The E300 and Rebel XT are DSLR (digital single lens reflex) cameras.
The A200 is not.
You cannot change the lens in the A200.
If the DSLR prices are beyond your budget the A200 is a good choice.
Here is a review of the A200:
I am looking to move up and over to digital. I am going 8 megpix (for quality blowups/heavy cropping) and want to be able to do some sports/action shooting so I need a decent zoom (7x - 10x). I would like to avoid anything too hard to learn to use.
I had narrowed it down to the Olympus E-300, the Canon Rebel XT, or the KM A200,
Problem: I see that the stock lens for the E-300 is only 3X so it would cost more to get the lens I need?
The Rebel is still a little too expensive.
That leaves me with the A200 - can its lens be change if I want to in the future?