This has moved: See http://github.com/twotwotwo/sorts/
radixsort provides parallel radix sorting by a string, []byte, or (u)int64 key, and a parallel Quicksort(data). sortutil sorts common slice types and adds functions to help sort floats.
Usually, stick to stdlib sort: that's fast, standard, and simpler. But radixsort can help if sorting huge datasets is a bottleneck for you. Try it if shorter sort times seem worth some hassle in your application.
To radix sort, implement sort.Interface plus one more method, Key(i int), returning the key for an item as string/[]byte/(u)int64, and call radixsort.ByString, ByBytes, ByUint64, or ByInt64. Set radixsort.MaxProcs if you want to limit concurrency. See the godoc for details and examples: http://godoc.org/github.com/twotwotwo/radixsort.test
There's no Reverse(), but radixsort.Flip(data) will flip ascending-sorted data to descending. There's no stable sort. The string sorts just compare byte values; so é won't sort next to e. The package checks that data is sorted after every run and panics(!) if not.
I'd love to hear if you're using this. E-mail me at my github username at GMail, or contact me on Twitter (@rf).