I think I should post here continuation of my search for the best preparation way.
Unfortunately, In Skypecasts area there are a lot strange people that can just waste time. Once I even spent an hour to explain what TOEFL is. Moreover, people is not motivated enough. Therefore, Skypecasts is a good place to study only with previously organized group. Despite fail of this plan, I have realized this idea with my friend from the USA, who is teaching me speaking in exchange for GMAT math. But it is another story

I'm still seeking highly motivated people for group TOEFL study.