podcast recording setup

I am ready to set up for recording a seminar I am offering, in the hopes of offering it as a podcast or webcast in the future. The length of time is approx 4 hours.

I have a 2012 MacBook Pro, and a good USB mic. (But I also have a Mac mini at my disposal if needed, and a 2nd laptop available, also if needed.)

What do I need? Should I record directly to a different drive? I'm also wondering about software and hosting. Is iTunes the host or just a marketing tool?

What are others using? What is the easiest, Apple compatible setup? I read about Audacity, is there a better recording and editing software?

This is my first effort, any suggestions are welcome.

thanks!

Julie