A computer network that uses the computers on the "edges" of the network rather than a central point or the network itself. In short, peer-to-peer takes advantage of all the computers on the network to speed things up.
plug-in:
A piece of software that can be "plugged" into an existing program to modify it in some way.
podcast:
A digital broadcast that can be loaded onto a digital music device, such as an iPod or other MP3 player.
podcatcher:
A piece of software (also known as an aggregator) that goes out on the Internet and finds podcasts for download.
podwaves:
An analog to airwaves.
preamp:
Stands for preamplifier, an amplifier that comes before another amplifier. In the case of podcasting, the preamp usually powers the microphone.