It was confirmed at the Marvel TV Panel by a video announcement by Joss Whedon that Clark Gregg will be the main star for Shield TV show. Here is the quote.
”Phil Coulson, Agent of S.H.I.E.L.D.”
Pretty cool news for Clark Gregg fans. Agent Coulson will be back. But the thing is does this show take place before The Avengers movie or after. I guess we'll wait and see.