Nature published a free PDF about the wonderful successor to Hubble: The James Web Space Telescope – download it with no registration required:
http://www.nature.com/news/2010/101027/pdf/4671028a.pdf
Great download.
Also this week – a great composite photo of a Quasar (3C 186) about 8 billion LYs has been released by the Chandra team – this too is worth looking at and there are some great downloads of this unique photo as well: