Our friends from Mockingjay.net was able to catch that Sam Claflin, who will play Finnick in Catching Fire, is already in Atlanta, Georgia. By the way, for those who don't know, there are news that Jennifer Lawrence (Katniss) and Josh Hutcherson (Peeta) were already there but no one knows if Liam Hemsworth has arrived there or not. Anyway, here is Sam Claflin's tweet. He is not really saying directly that he is in Atlanta but Twitter was able to know where he is. So, there you go.
On the other hand, Maria Howell, who will play District 11's Seeder, also tweets that she is in Seeder mode for Catching Fire. Thanks to hungergamestrilogy.net.