If your cellphone service lets you check voicemail from an external number, you could use Skype and the sound-recording software of your choice.
Or you could just let another squirrel in the house to recreate the craziness that I presume you're trying to capture. I mean, it's for the blog...
Can you forward the messages to someone who does have a microphone?
I'm guessing it's related to the Squirrel Attack on one of Becks' roommates.
squirrel attack
Hm... seems to me the squirrel was just mindin' it's own business in the wrong place at the wrong time (although well, I guess just about any time would have been "wrong"), and was attacked by 'Smasher. So "squirrel attack" seems like an odd way of describing the incident.
Hmm. This is going to have to go via the analogue hole - most[^]all voicemail systems are all done in SS7, so there is no obvious way of exporting it to IT-world, and anyway your telco probably won't like it. (Damn, voicemail I could export and attach to stuff would be useful. As it is, it's just e-mail that takes longer to process and doesn't do anything useful.)
Search through your device's menus for a voice recorder option - most phones do have one, and most recent ones will produce an MP3 file. You might be able to run it during the message. Then IR/Bluetooth/cable it to the desktop.
When Armsmasher Attacks!
Tom knows how to pull hysterical voicemails off the phone and convert them to MP3s (damnit).
Well, if you're planning to ruin someone's life you should probably start by getting a lawyer.
Sidekick
Perhaps the ideal device for a Mineshaft user. (I was just trying to remember this morning who it was that had described Unfogged as a gathering place for sidekicks -- anybody help me out here?)
Voila. I don't know how useful that'll be, though (mostly I just wanted to link to Smasher's voicemail again). Those are mac-specific instructions, but if you google around for "skypecast" you should be able to find details on how to capture sound from phone calls -- it's actually somewhat easier on the PC than the Mac, I believe.
The only potentially hard part is figuring out how to get into your VM system from a number other than your cell. On most systems I've used that can be accomplished by dialing in, waiting for the recorded prompt to leave a message, and then hitting the star key.
I just remembered/read that you're using T-Mobile -- yeah, the star key should definitely work. If you're okay with temporarily changing your VM password and sending it to me, I can probably handle the extraction for you.
You can save sound to an MP3 through the MMS menu. Not sure if you can do that whilst a call is open, though.
(See here
And a big Thank You to Tom! I forwarded him the message and he's going to see if he can work some magic.