As I understand it, NIST approves crypto algorithms but doesn't cover specific implementations. I think I've read about IEEE approving hardware implementations of, e.g. AES, but I can't think of any organization that performs an analogous function for software implementations of crypto algorithms.
Corollary/follow up question: There are many open-source, freely-available crypto libraries; are any of these standardized/approved by any kind of regulatory body?
System.Security.Cryptography
namespace classes in the .NET Framework. But I am not positive... – AviD Apr 20 '11 at 10:52