Hardware --
PowerBook G4
Mac OS X - Version 10.4.7
Memory 512 MB DDR SDRAM
Wireless AirPort Extreme

For software I use Nicecast, Skype and WireTapPro for streaming and recording with the Nicecast recording the audio as well for backup. I use Audacity or GarageBand for post-production of audio. I have used a Planetronics headset with mic and mic mute/headphone volume controls, a usb LogiTech mic, and am now experimenting with an M-Audio FastTrack recording interface (mic pre-amp and digital converter) with a Shure SM57 mic.

For me the biggest hurdle initially was broadcasting from within the school network. I could not connect to the stream due to filters at schools so I had to be connected by the home team (Dave, Jeff, Alex, etc) and host from Skype which does work at the school. From home streaming is easy, but I had to work on making sure all the audio settings on the mac were set correctly so I could be heard on the stream. By watching the audio LEDs in Nicecast, I know if I am getting a signal from my voice as well as from the participants joining me. Echo/Sound Test Service (echo123 in Skype) will give you a connection to test this detail.