Google has added Docs support for Microsoft Word (.doc and .docx). When you receive an attachment with a document in one of these formats, you now have the option to open them in Google Docs.
To use this feature, simply click “View” at the bottom of a message that contains one of these documents, and you will be taken to the Google Docs viewer.
It’s great that Google is building out support for all these document types — it really does make “Going Google” easier. If Microsoft wants to combat this, they are going to have to start offering similar features — like the ability to open Google Docs directly into Word.