Just about any snail will be fine for a goldfish tank. I'm keeping Pomacea bridgesii, Pomacea haustrum, Pomacea canaliculata, Marisa cornuarietis, Viviparus malleatus, and Viviparus viviparus in with my goldies. All get along very well!
So your average "mystery snail", found in just about any LFS, would be fine.
However, a snail will NOT clear up your algae problem. The vivs are more apt to eat algae than the others, and the canas and haustrums will mow down brush algae pretty well, but all will need supplemental food of their own and won't make a serious dent on a bad algae problem. They will also produce a good amount of waste- almost as much as a another goldfish.
The algae problem is more likely a water quality, lighting, or overfeeding issue, which should be solved on its own before you think about adding more aquatic life to the tank.