bluetooth transmitter

I have an HP iPAQ h4150 PPC (Pocket PC). It has a built-in sound card, but:
the input is built-in microphone only, i.e. no input jack for microphone or
line-in. When taking sound recordings in the field, I often use my notebook
to record the signal from my sound level meter AC output and would like, for
convenience sake, to use my PPC. As the PPC has Bluetooth and WLAN built in,
a way around that would be to use a compatible Bluetooth or WLAN transmitter
with a line-in connection. In principle, something like a Bluetooth (or
WLAN) cell phone headset, but with line-in instead of microphone.

Anybody any bright ideas?

Looking forward to hear from you!