I have had several questions on how to take out e-books from the public library. This article in Wired gives a fairly decent how-to, which is applicable both in the US and Canada. For those of us who connect through our computers, you need your own (free) copy of Adobe Digital Editions. Those who connect directly to the library will need a copy of Overdrive’s or Bibliocommons’ software for your device. Most of the software can be downloaded directly from your public library.
Also, in terms of sharing e-books, so far, unless there is no DRM attached to the file, the only way to share is by sharing an account, for example authorizing another device to access your Adobe Digital Editions, or other user accounts.
Here are a few handy links:
Adobe Digital Editions: http://www.adobe.com/products/digitaleditions/
More info on DRM and sharing: http://dearauthor.com/ebooks/how-to-share-an-ebook-without-stripping-the-drm