For teachers who are getting on board the Google Apps bandwagon, Doctopus might make the sharing and managing of assignments in Google Docs significantly easier.
It uses your class roster to create a copy of an assignment for each student, shares it with them as an editor and sends them a notification. All the copies off the doc are shared in the same folder and you can set up naming rules (no more Copy of Assignment1...). When you're ready to assess, you can actually automatically change all students back to having view only access at the same time. If you'd like, it will also email marks and feedback to students.
It does take a lot longer to set up and share than just pressing the "Share" button, but the advantage is that you aren't relying on students to create the document and share it with you. You can also see all of the student assignments, when they were last worked on (edited) and link right to them from the doc.
Thanks to Richard Byrne at Free Technology for Teachers for the tip.