I haven’t tried it yet… but Penguin is now offering (what they call) ‘ebook tasters’. These are files are from upcoming or newly released books, in a digital download form. It seems they are only available in ePub format which means you’ll need an ereader or Adobe Digital Editions installed on your computer. I’m sure all of this is a DRM move, which I’m not sure is a wise thing, if you’re only giving away samples. Wouldn’t you want to make that as hassle free as possible?