A couple of Sponichi articles on Yu Darvish and Munenori Kawasaki:
When Nippon Ham GM Masao Yamada was asked about what the team's plans were with regards to Yu Darvish and posting, Yamada said, "Players have to come to us and ask to be posted. It isn't our job to walk up to players and ask them what they plan on doing."
It seems the Fighters, in general, do not approve of posting players. However, they will make exceptions depending on the situation (taking into account both the team and player asking to be posted). If Darvish were to ask after the season this year, the Fighters will most likely listen.
Mentions that while all 30 MLB clubs consider Darvish to be a better pitcher than Daisuke Matsuzaka, teams probably won't dish out as much on posting fees. The article also notes that the timing of when Darvish gets posted will be important.
Seattle Mariners scout Yasushi Yamamoto was on hand at last night's game to watch Kawasaki. His comment on Kawasaki: "I think he's a better defender and runner than Tsuyoshi Nishioka and Hiroyuki Nakajima. I think he'd find a role as an everyday player if he could bat at least .250 at the MLB level."