"packet" and "package" are synonyms when we refer to mailings, but does the same apply to "network packet"?
My co-worker frequently says: "network package". It's like nails on a chalkboard to me, but is it correct?
Packet and package are certainly different in IT terms.
A packet is a small piece of data, that needs to be combined with other packets to create a whole. This is how data is transmitted over a network, by breaking it into packets of a few bytes: http://www.computeruser.com/dictionary/packet/
A package refers to an entire piece of software, that can be installed and operated by a user: http://www.computeruser.com/dictionary/software-package/
A software package would be broken into packets to be sent over a network, and the packets would then be reassembled into a package at the destination.
Network package is technically incorrect, although the meaning can be easily inferred.