Recording Cell Phone Conversations

I've been thinking it would be cool to do some interviews for my other blog as a way to expand its reach into original reporting.

Naturally, my thoughts turned towards recording those conversations. Since many/most interviews are done over the phone, and I don't have a landline, I'd need a way to record cell phone conversations.

The easiest way to do this would be some device that plugs into the hands-free port.

Ideally, the device would be small, use CompactFlash as the recording medium, record as MP3, WAV, or some other standard format, and have a USB port for connecting to a computer for downloading the recordings.

So far I've found two recorders:

Micro Cellular Recorder uses a microcassette tape and can also be used as a regular recorder for face-to-face recording.

Hands-Free Cell Phone Headset W/ Recorder is a little digital doo-dad with 16MB of flash memory for up to 120 minutes of recording time. This sounds cool, but it's spendy, and I wonder if you can replace the flash card with a larger one.

Know of any other devices that do this? Let me know.