The Y-Wing was an assault starfighter used primarily by the Rebel Alliance in the Galactic Civil War. It could also be used as a bomber, but for some reason they tried to use them as fighters first and formost...even though they were slower than snot. The Y-Wing was usually referred to as a big rock with engines...but even that description would probably give the Y-Wing too much credit. Y-Wings, though an older starfighter, were used extensively in the Battle Of Yavin as well as the Battle Of Endor.
An earlier model was used in the Clone Wars as well. These models had a lot more armor on them and were apparently pretty good, but the Rebels had to sell the armor and cool stuff for scrap in order to afford helmets. But they were really sweet helmets with all kinds of custom decals on them, and they really helped protect the pilots against TIE Fighter cannons. Well, that's what the dealership said anyway.
Some Y-wings had two seats so that the pilot didn't have to mess around with the guns. During the Battle of Yavin, the one-seaters were used so that they didn't have to waste gunners on what was obiously a suicide mission. Why they were even used during the Battle of Yavin is a mystery, since TIEs could easily keep up with X-Wings. In all reality, the Y-Wing is like the fat kid on a track team....totally useless.