The JavaMail(TM) API provides a set of abstract classes that model a mail
system. The API provides a platform independent and protocol independent
framework to build Java technology-based mail and messaging applications.
The JavaMail API is implemented as a Java platform standard extension. Sun
provides this royalty-free reference implementation, in binary form, that
developers will be able to use and ship.

WWW: http://www.javasoft.com/products/javamail/index.html