A guy named Gregory Chudov at the Hydrogenaudio forums just released the first version of his CUDA-based FLAC encoder. For the first version, performance is quite good, so this may be of use to some of you with higher-end NVIDIA cards who do a lot of FLAC encoding, but for those with quad cores and a MP-aware encoding frontend, this won't benefit you much.
His post is here. Some performance numbers are here.
His post is here. Some performance numbers are here.