For a good summary about how other people do it see How we do our home work which documents how the Home Work podcast gets recorded and post-processed:

1. QuickTime for audio recording
2. GarageBand for audio editing
3. Levelator
4. Sound Studio to adjust the sample rate, mix down to mono and add metadata

Depending on your setup and your quality requirements you can at least combine #1 and #2 by recording directly in GarageBand and also add intro/outro parts.

For a good summary about how other people do it see How we do our home work which documents how the Home Work podcast gets recorded and post-processed:

1. QuickTime for audio recording
2. GarageBand for audio editing
3. Levelator
4. Sound Studio to adjust the sample rate, mix down to mono and add metadata

Depending on your setup and your quality requirements you can at least combine #1 and #2 by recording directly in GarageBand and also add intro/outro parts.