Google Book Downloader is a cool piece of software that lets you download books from google availble to you and availble to you as Full or Partial View. All you will need is the ISBN number or Book URL or even by searching.
Also Look out at the complete tutorial which gives you a complete explanation on how you can use this software with screen shot and also how you can download google books availble only to US citizens.( As it claims It uses the Geo Location hack to do it) . Here is snapshot from the tutorial page.