Thank you very much Skyprince. First one is "Song Of Bangladeshby" originally sung by Joan Baez. I think the second one is written by Sikande Abu Zafar (my very favorite) - someone correct me if I abu Zafar is not the writer. In this video clip Rajib is singing the song in NTV's Closeup1 (Bangladeshi Idol).
These two songs were very popular during and after the laberation war.
I'll add some links to rap/pop songs too, when I find some. I'm sure some others will provide some links too.