I do not know if there are any real blogs by the actors. There may be.

There is the fictional "diary" on the abc.com site - see thread in Lost Discussion on this forum.

Over on The Fuselage, they have a forum with a "Got Questions for the VIPs?" section,
http://www.thefuselage.com/Threaded/...splay.php?f=10
In some of the replies there, (I was reading "For Javi" and "For William Mapother", I think) they say the folks on MySpace claiming they are lost insiders are bogus.