While this app has the exact same name as the iOS app we listed above, it’s made by a completely different developer. This version includes customizable skins and the ability to record calls or notes as MP3s. Instead of having to tap a button, you can also simply shake your phone to instantly start recording a call. You can also choose to sync your stored calls with Dropbox and select particular contacts whose calls you always want to record (and store).
Tap Record a new greeting. Note: If necessary, delete an existing greeting (limit of 2 greetings) to make room for the new greeting: Tap the Menu key, tap Delete greetings, tap the check box next to the desired greeting, and then tap Delete.

The simplest, lowest-tech option—beyond operating a recorder while you blather over the speakerphone—is a cable: the Olympus TP-8 Telephone Pick-up Microphone for under $20. It doesn't digitally capture from your iPhone. Instead, it has a microphone built into the earpiece. Plug the 3.5mm plug on the other end into a recorder. Hold the iPhone up to your ear to talk normally. The TP-8 captures each side of the conversation from what comes out of the iPhone's ear speaker, while you can still hear the conversation.
17. "Hello! You've gotten the voicemail of [your name]. Leave your name, contact info, and the answer to the eternal question ‘Which came first, the chicken or the egg?' Anyone who gets it right will receive a call back."