We have added several packages to Scientific Linux 4.6 that were not in the Scientific Linux 4.0, 4.1, 4.2, 4.3, 4.4 or 4.5 releases.

Alpine
Summary : Alpine is a tool for reading, sending, and managing electronic messages. Alpine is the successor to Pine and was developed by Computing & Communications at the University of Washington.
Added because support for pine has ended. This is not installed by default.

Java
Summary : Java has been changed from 1.4.2 to 1.5.0.
Security updates for 1.4.2 were causing problems.