While it may not be the most popular application among the Android faithful, Google Books is still a pretty solid e-reading app. A small update has sneaked out into the Market today, although at present it doesn't seem to be showing up in your my apps -- kind of like how YouTube went un-noticed.
The changelog on the Honeycomb upwards version -- and indeed the web market -- touts accessibility support/TTS, ability to remove a downloaded book from your device (pretty sure we already could?) and improved stability.
Over in the Gingerbread and below camp, the changelog reads very differently. Here we get fixes for download error messages. In both cases the version numbers are bumped only very slightly, so we'll go out on a limb and say its a bug fix update. Either way, you'll find download links after the break.