cvsroot is a script to help keep track of multiple sites when using CVS, and in particular the CVSROOT and CVS_RSH environment variables for those sites. It creates a $HOME/.cvsroot file, with shortcut names representing the different CVS sites. The new environment variables appropriate to the site selected will then be set, and a new shell will be spawned to keep the variables. In this way, you do not have to keep setting the environment yourself, and can rely on the script to keep track of things for you.
CVSNT was started as a port of cvs pserver for NT. It has since been greatly improved and is now available under Windows, Unix/Linux, and Mac OS X. Authentication may be done via all standard CVS protocols, plus Windows-specific SSPI and Active Directory. Secure transport support is implemented via sserver or encrypted SSPI. The NT version is fully integrated with the Win32 system. MergePoint processing means no more tagging to merge. Atomic checkouts mean you always get the files you wanted.