This is the wrong place to look for a boost in search engine rankings.
Sure, an ODP listing may give such a boost. But here's the rub, anything it does for YOU, it does just as well for all your competitors -- and it may do for them FIRST! (Someone has to be first, but online nobody knows you from Adam's second-favorite housecat...so it might not be you.)
Make your plans based on the assumption that your site won't be listed in the ODP. That way, if it isn't listed -- you'll have done the best thing. And if it IS listed, it will get that (possibly mythical) ODP boost, ON TOP OF your best work. So, either way, listed or not listed, you'll have done the best thing.
The beauty of it is, if you think about it that way, you don't have to know whether it'll ever be listed or not. You just have to start doing the right thing, right away....