I went to the Dropbox site with the browser to get the apk and then found and saved apks to my Dropbox on my PC. Then I installed them from the Dropbox on the Fire.What I've found easiest is putting them on my dropbox (including the dropbox apk) then using the web interface to get the dropbox apk and then it's real easy to get the rest.
I downloaded the GetJar app and tried to download the Nook app for my Kindle Fire. It worked as far as getting to the app but once I tried to actually download the Nook App it came back saying No compatible version for the Kindle Fire was available. So .. at a loss as to what to do next. Any suggestions?