Yes, there are both open source and proprietary (Catalyst) drivers. The proprietary drivers have higher 3D performance, but the open source drivers work well on a wider range of distros.
Some distros include both in their releases, others only include the open source drivers. You can download the proprietary drivers from amd.com. If you download the proprietary drivers, please read the install instructions and release notes before installing - that saves a lot of pain.