Durood e Akbar is a mar'roof Durood Shareef which is commonly read. It is referred to as Durood e Akbar because it is said that it includes (almost ?) all the Sifaat e Jameela of Prophet (PBUH) in Jama'a andaaz. And it is also referred to as Akbar because of its length.
This Durood Shareef is in fact the explanation of the true heart feelings of Ashiqaan e Rasool (Sallal Laahu Ta'ala Alayhi Wa Aalihi Wa Sallam) so one who reads Durood Akbar will be enriched with Sa'adat e Daarain.
