I have the same question. Although nobody ever answered your question is this forum, were you able to find a solution?
Click on app store.
Enter Epub reader in the search field (upper right).
Second section down is for ipad.
There you will find several apps that are supposed to be able to read epub and pdf files.
No claim on my part as to what works, as I have no experience with ipad. I use a kindle.
One other point: the '.ascm' file is not the ebook itself - just a small
file containing data about where the ebook is located and some information
about its size, etc. When you go to download the ebook from the source,
your iPad ebook reader for '.epub' format will know what to do with that
Another thread pointed me to the Bluefire Reader app (free). It worked like charm to open the ascm file that I had purchased.
Message was edited by: musicwms