Google just published a new and very useful lab feature: Turn an email conversation into a Google doc:
More than once, I've had a conversation over email and later realized that the information contained in the messages would make a great starting point for a document. So I built an experimental feature for Gmail Labs that does just that: with one simple click, "Create a document" converts an email into a Google Docs document. No more copying and pasting the text from your email -- just open the message you wish to convert, click the "Create a document" link on the right side of the page, and voila, you have a brand new document which you can then modify and share!
There is even a keyboard shortcut for this new feature: g + w