The addition at this point does not include editing or saving PDFs, only the ability to read PDFs and paste into fields. However, it's a jump from having no PDF support at all. The Google Docs team claims that the inclusion of PDF support was prompted by Docs users.
Some very Google-esque features are currently missing from the PDF support function, including the ability to search through documents (that I could find) and a lack of mobile support. However, the feature is only a few days old – and will likely be even more smoothly integrated into the suite soon. Google Docs as a whole does suffer from a bit of a feature-lock, in that suites like Microsoft Office and OpenOffice have a veritable horde of functions at their disposal. Still, if you like the idea of office document collaboration, it's a fantastic tool.