Does anybody know if they've cast anyone to play Seth Clearwater?

I think that I heard that the one that played prince caspian in narnia will be seth. :(

No they havent casted Seth yet. But I'm not completely sure if he is in New Moon.

They Haven't Cast Anyone For Him Yet Becuase He Isn't In New Moon.
If I Remember Right, Seth Doesn't Come Into It Until Eclipse.
If I'm Wrong I'm Sorry But I'm Sure Seth Is A Werewolf In Eclipse So They Won't Have Cast Anyone.
:)

He is in New Moon but only as a passing character because he is described as idolising Jacob when they have dîner at Billy's, but he isnt in the film and i don't think they are casting for eclipse yet

umm no i don't think that they have cast him yet but i really hope they cast Tyler Posey i am a huge Seth fan he is the greatest person ever he is amazing and to all those people who say that he doesn't come in until eclipse are WRONG he comes in at the dîner party at Billy Blacks with Jacob Charlie, Leah, Sue, Harry and Bella. It may be a small part but it plays a substantial part in the plot line because it is when Harry Clearwater is introduced in person and Seth is described as being a gangly teenager who hung on Jacob's every word with idolizing eyes can toi tell i l’amour Seth i swear to toi that i did not need to get out a book to look up how Seth is described then in the third book he is described as a mini Jacob

I think they hired someone named 'Boo Boo Stewart'
........Funny Name...!!!

indeed, the actor that will be playing Seth is Boo Boo Stewart, 15 years old, and also a martial arts champion like taylor lautner.

Yes,they have.The guys name is "Booboo"Stewart.