The San Diego Union-Tribune had an interesting article on Saturday, Dec. 12, 2009 entitled "How Can I Preserve My Family's Memories?" by Jennifer Davies. The article has practical tips on how to capture the message, timing, location, preparation work, and other great suggestions related to recording audio memories.
On the technology side, Jennifer recommended the following potentially helpful resources:
Other technology options that I might consider recommending is a good USB microphone connected to a computer or if you wanted a hand held unit, I've read good reviews about Zoom H2 Handy Portable Stereo Recorder (but I've not used one).