FECpp is a BSD-licensed C++ forward error correction library. It is based on fec by Luigi Rizzo. It supports using SSE2 to optimize the GF(28) multiplications, which is the most computationally intensive portion of encoding and decoding.
Wrappers for Python using Boost.Python are also provided.
I wrote more about the library, particularly the SIMD optimizations, in a blog post.
Current released version 0.9 (2010-03-12): fecpp-0.9.tgz
Sources are also available on github