I will travel by train and by bus between some of Eastern Europe " contruy inFeb 2008 please advise?

Would be nice if you could give some more details about your schedule. What do you call Eastern Europe?

Is you decide to go through Baltic countries you can choose bus or train (both is OK and not expensive), same is for Poland, Czech Republic or so. But if you think to reach Roumania, be prepared to deal with some transportation or infrastructure problems. Also in this time of the year it will be really cold and lot of snow.