I was asked a few weeks ago to create a cheat sheet for eBooks so our staff could have something to reference and handout to the public. Luckily I had just read a very helpful post by Jason Griffey that really summed up a lot of issues with eBooks, file types and DRM. I asked in the comments if I could adapt the post and he said it was ok. So I did.
It's actually a pretty useful cheat sheet for everyone, not just librarians. BTW, the PDF is actually 2 pages. The second page is the ereader cheat sheet that Overdrive released. It's not as useful, IMO.