Just got an email from Fictionwise saying that eReader for Android is now available. It will run on Android 1.0 and later, with 1.5 or later recommended. It will run on the new 2.0 release. The FAQ list sthe software as beta, however. According to the FAQ, you can also purchase books from eReader.com and fictionwise.com from your mobile Android device.
The download link is on the FAQ page.