Hi Doug. If I'm at a conference and sketchnoting the presentations and am keen to get those sketches onto Twitter in real time so that they contribute to the conference back channel, I use my phone. I used to use the free CamScanner app for iPhone, as it does a great job of applying a filter to whiten the whites, darken the blacks, and adjust any distortion in the framing of the image that you photograph. However I recently uninstalled the app as it was revealed that it contained some code that left the phone vulnerable to a remote attack. So I'm on the hunt for a replacement phone scanning app (there are probably a dozen out there, I just haven't looked yet). For the conference that I attended this week, I just used the standard camera app: https://twitter.com/mattymcg/media
However I always scan my sketches using a flat bed scanner when I get home from the conference. The phone camera is OK but there's no substitute for a high res flat bed scan of your image, especially if it's going to be shown to a client or something.
In terms of where I scan them to, I don't use anything fancy like Evernote or Adobe Bridge. I just have a methodical naming convention for the folders that I store files in, so that's where they go.
Hope that's helpful!