The latest version is in the W2k3 Resource Kit Tools; it should work in W2k8 as well:
Windows Server 2003 Resource Kit Tools
http://www.microsoft.com/downloads/details.aspx?FamilyID=9D467A69-57FF-4AE7-96EE-B18C4790CFFD&displaylang=ensrvany itself shouldn't cause any stability problems; it's just a relatively simple service wrapper that just starts and stops the application specified. Whether the application you'll be running as a "service" will cause stability problems depends not on srvany.
There's no x64 version of srvany; you can only run it as 32bit service in a 64bit OS.