extracting sound recordings from voice memo iPhone

I recorded some guitar lessons, each about 30 minutes long, using the voice memo app on iphone OS 3.1.3. How do I copy them off the phone and onto the computer? I tried to use iTunes, but I cant seem to access the recordings. If I try to sync with the computer, it threatens to erase the sounds in the phone. How do I extract these recordings from the phone and put them on my computer? Is there some other software I need to have?
Macbook Pro Mac OS X (10.6.6)