It looks like the Shortcovers name was short lived. I found out that they have rebranded as Kobo and according to Kyle @BBCool they have teamed up with Borders. They already have a BlackBerry app which lets you download eBooks on your BlackBerry.
They are also planning on offering 1.8 million free books with an additional 200,000 bestsellers for $9.99 each. The app is limited to OS 4.5+ but that includes most devices.
Check out more details at this link. You have to enter in your email address to be sent the OTA download link. Personally I am sticking with Mobipocket but I like the fact that there are alternatives coming to the BlackBerry.