Motricity has released an update of the eReader e-book reading software, adding official support for Windows Mobile 5.0-based devices. Version 2.6.3 also adds a couple of bugfixes since V2.6.1.
You can download the trial of eReader
from here. For the first 15 days you'll have free access to the Pro features; after that you either need to purchase a registration or continue using a crippled version.