Carnegie Speech is another good product in this area, that as the name suggests came out of Carnegie Mellon a number of years ago (I have no affiliation with the company).
I think one advantage I have over this product is, SayAfter.me stores ever growing stats of word/phrase pronunciation attempts from all users.
Later on it can build custom exercises depending on the background of a particular user.
I will be able to say "You are Spanish, other Spanish users had the most trouble with these words. So here is an exercise that contains problematic English words for native Spanish speakers".
This thing wouldn't have been possible without Google really.