"Additional" (the only) storage card it supports is SDHC. I used a transcend 32GB class 10. It does not have an external Mic socket - so you can only use the in-built microphone. It records to H.264 MP4 file as AVCHD.
Check out my review and go to my link where I have posted a video made by this camcorder. It has lots of noise from the focusing motors etc. It has a great lens if you don't need sound. I am finding some issues with what may be the image stabilizer, some shakiness not associated with my handling the camera. I use a 32 gig class 6 and it works great. I read that class 10 may be overkill for this type of camera. I am only using it for hiking and outdoor stuff so the sound issue is really bugging me. I got it as a free gift otherwise I would have returned it and found a quieter camera.