This question already has an answer here:
What epub readers will sync between my Android phone and rooted Nook Simple Touch? (I mean my place in a book, not the books themselves.)
I tried PageTurner - and, while it works, it's ugly as sin. Text looks awful, margins are bad.
Ideally I'd use Google Books, but it won't run on my Nook. I tried version 1.6 (I think) and it opens, shows covers, then crashes.