If you saw the Smart Cover during that announcement a while back and have really wanted to use it with your iPad 1 instead of buying a whole new iPad 2, you may be in luck. One enterprising blogger named Dan Provost agreed with you, and he found that if you super glue a few rare-earth magnets to the side of the iPad 1, the Smart Cover can fit quite nicely right along it. It's a little hacky (depending on whether you mind having a few magnets super glued to a device as slick as the iPad or not), but since we know the Smart Cover is really just magnets and fabric, it should work great.
Of course, if you don't want to go that route, there are cases for the iPad that will happily do what the Smart Cover does without requiring you to do any gluing. But if you want Apple's solution for the second iPad to work with your beloved first version, this might be just what you're looking for.