I have a bunch of the digital Project Life editions so that I can print whatever cards I need rather than buying all of the core kits in physical form - I have a bunch of extra cards from other core kits that I know I won't get to (because every time a new product comes out I just have to use that one!). Remembering which cards I have though is very hard, and scrolling through folder after folder on my computer to figure it out is way too time consuming. I found a solution to my problem last week and wanted to share.
On my Mac, I uploaded the card PNGs to iPhoto, selected them, and clicked on file/print. I chose "contact sheet" and then "customize." From there you can change the number of columns on your sheet so that you can make them the size you want. I didn't need very large images so I opted to print them small and save paper. I printed mine on card stock but that's personal preference.
I printed the journaling and filler cards, and the bifold cards from each edition, and the first and last page cards as well. (I didn't bother with the digital papers - I can look for papers when I want them).
Then I just slid the pages back to back in page protectors and stuck them into a 3 ring binder.
I haven't had a chance yet but the plan is to use some tabs to label the different sections in the binder for each edition.
So simple! I did this on my Mac with iPhoto but I did a very quick google search and there is supposed to be a way to do this on a PC using the native Windows photo viewer. If anyone knows how to do this please feel free to add the steps in the comments.