Well done anyway. It will save you massive amount of time developing a new application.
I was actually looking at building something similar. But since you've mentioned CodeDom, I might actually check it out first before wasting my effort.
The other thing that I've notice is that the new version of VS.NET that is coming seem to have some kind of similar feature too. Correct me if I am wrong.
I haven't looked too extensively at the source code that was generated by your tool but from what I can see you've only handled code gen based on table schemas but not really taking care of relationship between the tables? Perhaps that's something you could
improve on? Just a thought.