CVS is one thing that'd profit greatly from having data, let alone password/username, being sent over Internet (or local LAN) in plain text. There seem to be some SSH solutions and SSL. It'd appear that SSL integrates neater into CVS. SSL patches are available at http://freshmeat.net/projects/cvss/. The server side seems to require sslwrap though. For consideration.
Now that I think about it, it might also work with stunnel.
It would work with stunnel.
using either stunnel or ssh is a better solution. project has been abandoned; sslwrap would add just as must overhead (probably more) as stunnel