And here's a collection of Mahasi Sayadaw epub books. Download as you like:
This collection is taken from http://www.mahasi.org.mm/treatises.html. You can also download pdf versions from that site, but you will need a special font for that. For my version you'll need a reader that supports epub format. I recommend, as do many others, Calibre E-book Management, for all your ebook needs.