Antimatter has opposite electrical charge (and magnetic moment) from normal matter. It should have the exact same mass and interaction with gravity as normal matter.

An anti-electron is called a positron because it has a positive charge instead of negative. Antiproton (sometimes called negatron, but rarely) is just a proton with opposite charge. You can even make a hydrogen atom out of an antiproton and a positron, called antihydrogen. https://secure.wikimedia.org/wikipedia/en/wiki/Antihydrogen