Download the Mobipocket version of an eBook (perhaps Frankenstein?) to your desktop computer.
Transfer the downloaded file to your Blackberry in the standard way.
Alternate: visit mnybks.net on your Blackberry and download the mobipocket
file directly to your device!
A few things to note:
When the download starts, you will be presented with the message “The item you selected cannot be displayed. Do you wish to save the item?” — Press Yes.
When the save screen pops up, select the folder icon next to “/Media Card/”. Then open the folder that says “Media Card”. Finally, select the “eBooks” folder and press open. Press Enter on the keyboard, then press Save. The saved file will be available the next time you launch Mobipocket.