I am a former Premier AP holder (my AP expired just after my trip, which was nice because I got to try out the AP PP offerings). As others have said, if you have the Premier AP (the AP that is good at both DLR and WDW) you are "grandfathered" into the new PP+ benefits. You'll need to register your Premier AP with the Disneyland.com website and then under the Annual Passholder menu, you'll see Photopass link. Click that link and that's where you're PP photos will appear.
For the regular photopass photos - the ones taken by the photopass photographers, including the Magic Shots - I recommend getting a regular Photopass card. The photographers usually have these and can give it you. On the AP photopass page, you can enter the card's number and your photos will appear. You can enter more than one card. For the attraction photos, you will need to write down the number of the photo (including the letter at the start) and then enter that on the AP Photopass page. After you've finished entering the card and photo numbers, you can then download the photos. When I was last able to check, there were no options to edit the photos (i.e., crop, add borders or stickers, etc.).