Barnes and Noble Ereader Mobile Download
Good news: it's spiffy.
Set up your online account, install the free app, log in. Downloaded books save to your SD card.
Bad news: looks like the reader won't work on things like PDFs that you already own. At this point you're pretty much locked in to free eBooks from Google, and the eBooks you buy online from B&N. So I'm not getting rid of Mobipocket just yet.