Online Book Reader: GooReader 1.8
Link: Read Google Books on your desktop | GooReader
It works on Windows XP/Vista/7. And you need to have .Net Framework 3.5 SP1 installed on your computer.
Searching for Huckleberry Finn [and selecting 'Only Books with Full View'] yields 253 results.
In the free version you cannot save the book[s] you have found to PDF format.
Download supplied in ZIP file format. The ZIP file contains setup.exe and GooReaderSetup.msi. I was able to deploy the app just using GooReaderSetup.msi without any modifications.