Does Plato have anything good to say about Poetry?
Not really. He says many things such as poetry cripples the intellect and it is memorized dribble solely for the purpose of preaching and teaching others. Remember, though, that Plato is mostly focusing on the poetry of the Greeks and that it is a way of life (oral, not written to be read later) that is not familiar to us. He is not addressing poetry as we know poetry today.
Check out London author Eric Havelock's review of Plato's Republic below for more help on the issue.
Actually he does have good things to say about poetry. Don't just look at a review of Plato's Republic, look at Plato's Republic (I recommend Allan Bloom's translation). He seems to have mixed feelings on poetry, or at least he shows Socrates as having mixed feelings.
At one point he says poetry is necessary to the perfect republic because it's the only thing that can convince people of falsehoods (which would be at the foundation of the republic--a myth of people being born from the Earth and in different classes from the start). Yet their ability to convince people is the reason for his dislike of poets in the allegory of the cave much later in Book 7 of the Republic.
After he says it's necessary, he soon says poetry must be banned. One of the reasons is that it contains falsehoods in its imagery (many of his complaints can be found in Books 2 and 3 of the Republic). But then he ends the Republic with the myth of Er, a thing of fiction, and in many respects a poem. This makes us question his opinion of poetry and shows perhaps his hopes for poetry when his own words are compared to his earlier complaints.