Quote Originally Posted by zorro View Post
сегодня я (received)только одно письмо от брата, но завтра я, наверно, (will receive) 2-3 письма от своих друзей.
Is the first получил and the second буду получать?
I'm pretty sure you should use the perfective future (я получу) even though there more than one letter will be received -- after all, you expect that several letters will be delivered simultaneously, on the same day. However, I think you could say:

В декабре я буду получать много писем от друзей.
(In December, I will be receiving many letters from friends [i.e., over the course of the entire Christmas season].)