No!  Never release a captive animal back into the wild, especially if it's
a species that's not native to your area.  The animal will either die, in
which case you didn't do it any favors, or it won't, in which case you have
just introduced an exotic species into your local ecosystem.  This Is Bad;
the most drastic example among herps is the giant toad (_Bufo marinus_),
which created ecological chaos when it was introduced into Australia for
pest control (and it didn't even work for that).  Even if your herp is a
native species, it may be carrying pathogens that shouldn't be released into
the wild, and if it was captive-bred, its genetics may have drifted enough
that you're introducing destructive genetic material into the wild population.
The problem of pathogens is not just theoretical; some wild populations of
herps have nearly been destroyed by well-meant releases of captive animals.

If you have a native herp that was caught in the wild, and you know exactly
where it was caught, and you're very sure it hasn't been exposed to any
pathogens while in your care, and it hasn't been in captivity too long, you
*might* think about releasing it.  Even then, it probably isn't a good idea.

If you really can't keep a herp (or other pet), try to find it a good home.
If nobody wants to take it, a local herp society might be willing to put it
up for adoption among its members.  Zoos generally will not accept donations
of this sort (they have enough Burmese pythons already), but if you have
something really unusual, it couldn't hurt to call the zoo and ask if they
want one.  Or you can sell the animal to a pet store, though it behooves
you to find a good, responsible store that keeps its animals in decent
conditions.  Just don't let it go.