Recording speaker output on MacBook with OS X Snow Leopard

Solution 1:

I would use Soundflower and make the output and input Soundflower via the "Sounds" preference pane in System Preferences.

Solution 2:

I would use Soundflower with Audacity.

Soundflower is a Mac OS X (10.2 and later) system extension that allows applications to pass audio to other applications. Soundflower is easy to use, it simply presents itself as an audio device, allowing any audio application to send and receive audio with no other support needed. Soundflower is free, open-source, and runs on Mac Intel and PPC computers.

Audacity is free, open source software for recording and editing sounds. It is available for Mac OS X, Microsoft Windows, GNU/Linux, and other operating systems.