At the you can find some huge lists of American names . They are divided into lists of American male, American female and American surnames.
Obviously, if you're writing code in C, this option is not available. But for C++ programmers with access to a C++11 compiler, you should probably forget that rand exists and use the new <random> library. If you don't have access to a C++11 compiler, the Boost library is the order of the day to get a decent facsimile of the standard <random> library. Boost is awesome in general, and I'd recommend checking it out as it contains a lot of libraries and acts as a test bed for additions to the standard.