^
1. The suffix is pdb for the base file; it expands upon opening to three different files (can't remember their suffixes and too lazy to look atm...) I'm pretty sure at least one of them is a page history/etc.
2. You have to supply the name of the person the account bought under and the credit card number that was used to purchase the book (and/or that was registered at the time of download. To change the CC number that it's downloaded under at eReader.com you have to use that number to purchase at least one ebook.)
3. eReader software (basic) is free at eReader.com. I don't know about the asker, but (even though I've seen you post much,) I'd be really uncertain about supplying a live credit card number to anyone I met via a forum. --Except my wife...
