The character is voiced by John DiMaggio (no relation to the baseball player).
Bender was created as a bending robot - his function was intended to be bending metal girders. However following his encounter with Fry he broke his programming. Of Asimov's three laws the only one he (usually) follows is the first part of the third.
He is best known for his heavy drinking, however this is not his fault. Robots of his type use alchohol as fuel - Bender only actually becomes drunk when he stops drinking!
It's hardly surprising that Bender has a slightly warped personality. After all, his mother is a robotic arm, his father was killed by a can opener and he has an Aunt who is screwy. Literally: Aunt Rita is a screw.
There are various mathematical jokes in Futurama, some of which involve Bender. For instance, Bender's apartment number is 00100100. This is the binary representation of 36, the ASCII code for the dollar sign ($). Bender is also said to have been his mother's 1729th son, 1729 being of course the famous Hardy-Ramanujan number:
This could be why Bender's serial number is also the sum of two cubes:
Bender is a favourite character with viewers and stores alike - you can buy all sorts of merchandise associated with the show. These include model Bender figures that, in some cases, are themselves bendable!