Sumatra PDF is a slim, free, open-source PDF viewer for Windows. Sumatra has a minimalistic design. Simplicity has a higher priority than a lot of features. It's small and starts up very fast. It's designed for portable use: it's just one file with no external dependencies so you can easily run it from external USB drive.
What's new in this version:
Version 1.1 added "File/Properties" menu item, showing basic information about PDF file.