That New Jersey ACLU Record A Cop app is very popular, and from what I understand, it dumps recordings to their servers real time so it's off-site if the phone is confiscated. I do have to wonder how many odd recordings they get, but that's beside the point. I have this on my Galaxy Note (Android), but I know it's there for iPhone as well.
As far as a recorder, I use a little Sony ICD-PX312. It fits perfectly in place of a spare mag for my XD .45 in the dual mag XD Gear belt carrier, but I usually keep it on a neck lanyard. I let it record all day in super high quality mode, then dump the recording when I get home if nothing happens. I also record to the micro SD card so I can, maybe, snag the chip if there is a demand the recorder be handed over.
I was stopped last Thanksgiving night (see my thread about this) by UHP heading in to work. The recorder was under my shirt, under my jacket, and you can hear everything clear as a bell. I locked that recording and still listen to it from time to time for a smile. It's quite a nice little unit, and with rechargeable batteries, runs easily 36 hours with no recharge. I got it for ~$40 at Smiths.
801-550-3426 (texts are best, but call if you like)
NRA Endowment Life Member, Pistol Instructor
Gun Owners of America Member