copyright notice

[Mike Schwartz]

A couple of points and questions.  

Is it sufficient to mail yourself a copy of the source (and leave it
postmarked and unopened) to protect a "copyright" ?

Is a header that says something like:

(C)1986, ABC CORP. All rights reserved!
Feel free to distribute this on a non-profit basis.

enough to keep a program from being public domain, yet freely distributable?