Episode 7 was supposed to be "Autumn Storms" then it got changed to "Chains". A few days ago GRRM said on his blog he'd changed the title and gotten a song instead. Now it makes sense. (I totally don't feel geeky after saying this..)
Interesting episode titles imo. "Valar Dohaeris" follows up the season 2 ending "Valar Morghulis", which is a nice thing if you recognize it . It also seems there are a lot more quotes and songs in the titles, very different from the previous seasons and episodes - "Dark Wings, Dark Words", "And Now His Watch Has Ended", "Kissed By Fire", "The Bear and the Maiden Fair" and "Rains of Castamere".
Should be interesting to see who Mhysa is, I'm assuming it's a name. Can't recall anyone in the books named that, anyways.