I have a similar project...
I'm working on a similar project, I'm going to log 8bit, mono, but at 8khz, to a microSDHC card
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My favorite PIC is the 18f4550, but I think I'll have to choose a more appropiate chip in terms of footprint and power consuption, because the end device will be battery powered, and I want it to be tiny.
For the microSDHC interfacing I'm using the dosonchip.com, they claim it can handle cards of up to 32Gigabytes.
I plan to read the files in my PC directly from the uSD; It shouldn't be a problem for you to add a DAC or use a PIC with DAC, a simple amplifier and a 3.5mm jack.