Details from http://en.wikipedia.org/wiki/Alucard_%28Hellsing%29
Alucard (アーカード, Ākādo?) is a fictional character and the protagonist in the Hellsing manga and anime series created by Kouta Hirano. He is devoted to his master, Integra Hellsing , and gets along well with the butler Walter C. Dornez. He also has feelings of affection towards his fledgling Seras Victoria. A powerful vampire, Alucard works with the Hellsing Organization against other vampires and evil forces. He has a range of supernatural techniques including enhanced strength, the ability to change shape, hypnotism, powerful regeneration, and others. He fights with ferocity and often extreme cruelty, rarely killing until his target has been disabled and humiliated, while frequently allowing enemies more than one chance to kill him. According to Volume 8 of the manga, he is Count Dracula (Alucard is Dracula spelt backward). Soon after the events presented in Bram Stoker's book, Van Helsing gains control of Dracula, renaming him Alucard, and leaves him as a servant of the Hellsing family. The manga takes place over a hundred years later, when the Hellsing organization is forced to fight remnants of a WWII Nazi organization.
He typically dresses in a distinctive Victorian and western fashion, with a charcoal suit, leather riding boots, a red cravat, and a long red duster (which resembles what Van Hellsing once wore). He also wears a red fedora with a wide, floppy brim and a pair of circular, wire-framed sunglasses. However, this form seems to be a part of his being as he can change it at will.
In the anime (both the TV series and OVA) Alucard is voiced by Nakata Jouji (中田譲治). Crispin Freeman voices him in the English dub of both series.