Literary agents Juliet Mushens (The Agency Group), Julia Churchill (The Greenhouse Literary Agency), Juliet Pickering (Blake Friedman) Jo Unwin (Conville &Walsh) and Molly Ker Hawn (The Bent Agency) in some combination, give up around 45 minutes to answer any questions tweeted at them, using the hashtag #askagent. The time can be a little variable, 8pm or 8.30pm GMT but it is there or there abouts (Seems agents have lives too. Who knew?)
It isn't always easy or cheap to meet agents, let alone to pound them with everything you wanted to know about agents and publishing, but this is a fab way to get a direct answer to those questions in a matter of minutes. (You can of course go through all the past questions searching Twitter via the hashtag, which will bring up questions from all over.)
At the very least it is worth lurking and following the questions. It's honest responses, it's free and you don't even have to leave the house.