This one supports ePub to my knowledge and has for a while now.
The Mobipocket Reader for Windows Mobile
Try the Mobipocket eBook Reader on your PocketPC or MS Smartphone device, and enjoy the reading experience. The application is free and then you can buy ebooks 24 hours a day, 7 days a week from your PC, and also from everywhere if you buy from your device. Get below an overview of the main features of this application.
Install it from your device:
Try the OTA (Over The Air) installation: simply go to
http://m.mobipocket.com/ with the webbrowser of your device. Then follow the link "Download Mobipocket Reader" and choose "Windows Mobile PocketPC" or "Windows Mobile Smartphone" if you have a MS Smartphone device.
Install it with your desktop PC:
Install the
Mobipocket Desktop Reader, run it, and connect your Windows Mobile device with Microsoft ActiveSync. Your device will be automatically recognized by the Mobipocket Desktop Reader, which will guide you through the installation process.
Install it manually:
Find the .cab setup file for manual install
here. Transfer this file to your device with ActiveSync or with a memory card, and run it on your device to launch the installation process.
Immersive Reading Experience : Better than paper
Mobipocket eBook Reader lets you customize your reading experience. Find the most adapted font family, and font size for your eyes. Customize margins, line spacing, full text justification, font color, background color... Choose your way of what is the best reading experience. Use the fullscreen mode to take advantage of the whole screen. Turn pages simply with the scrollwheel or by pressing the right arrow key.
My Library : See and find all your ebooks !
All your digital books stored on your local device are listed here. The library view will let you sort and filter all your ebooks (by memory location, author, file size ...) You will also be able to rate your ebooks and assign them to your own reading lists.
Annotations & Highlights : It's Your Book
Mobipocket eBook Reader gives you plenty of tools to annotate, bookmark, highlight, any part of any eBook. Then synchronize and save them all on your PC with the Mobipocket Desktop Reader and send them to a friend or to one of your other device !
Search and Lookup : It's built-in
Lookup any word with the multidictionary search function (Simply select a word and choose lookup in the contextual menu). The lookup feature even does the disinflection and spell correction if needed. Choose between hundreds of
reference dictionaries from world renowned publishers in the eBook Store.
Mobipocket eBook Reader 5.2
Install it from your device:
http://m.mobipocket.com/
Install it with your PC:
Mobipocket Desktop Reader
Install it manually:
Download .cab file