ShareBuilder is already listed on ING Direct's product page. In the last year, ING Direct has been on a growth binge in adding new products. From the Internet Archive you can see what their product page looked like a year ago. In addition to ShareBuilder, they've added the Electric Orange checking account and business accounts. And in September, ING Direct acquired the accounts from NetBank after it was closed by the FDIC (see post).
For those who follow brokerage promotion deals, you're probably aware of ShareBuilder's new account promotions. Seems like every other bank or credit union lists some ShareBuilder bonus. This FW thread has a long list of them including those from PenFed, Compass Bank and SunTrust. With the acquisition by ING Direct, it seems likely we'll see some changes.
Thanks to the readers who mentioned this news in emails and comments.