Let me preface this by saying that you should check out Sketchup, it's free :)
The overall table isn't bad, per se. I'm concerned about your shelf construction. If they're not detachable, they're going to be a weak point when you move the table.
I would make a few suggestions ...
If it's possible, make the bottom one large shelf rather than splitting it into two pieces. If it is two pieces as it appears to be, then you might consider some options:
Add two more legs offset toward the center to act as support for the shelves. These could have ledges cut to rest shelves on, or hardware as rob recommended(I would use the hardware)
In this way you will be able to make each side of the table adjustable, and you can add in shelves as necessary.
You'll also need some support for your slotted shelves. The further in they go, the more support they'll have.
Below are two possibilities.
On the left, there are raised rails which push against the top of the frame and the shelf is extended further in.
On the right, the rails are offset, which allows them to be longer. both of these hinge on using the rail as a stop, to keep it from sliding out. If you want them to be able to slide out, attach the rails to the table rather than the shelves.
I would lean toward the left option since it would give more support to the rail. You will also want to reinforce the mouth of the slot, it's the fulcrum of "the lever", and will take the all of the downward pressure being applied.
Leave 1/16 inch above and on the sides of the shelf to allow for wood expanding.