I was on a conference call this evening with some other educators and administrators in the state of Maine. The purpose of the call was to brainstorm ideas for a video about preparing for teaching in a 1:1 computing environment. In advance of the call we were asked to generate a list of things that teachers should know before teaching in a 1:1 environment.
This is the list that I generated with some help from my Twitter friends @ernieeaster @scmorgan and @edtech4me

1. Not all teenagers are digital natives.
2. The computer itself is not going to create student engagement.
3. Teaching with technology is a heterogeneous experience.
4. It takes longer than you think to get a room full of students on the same webpage.
5. You should keep a list of students’ usernames and passwords.
6. Murphy’s Law is strongest the first few times you try to teach 1:1
7. Close and Focus.
8. Project design is still about the content.
9. Better to stand behind students than in front.
10. Network administrators are not always up to date on Web 2.0 from the end-user perspective. (There’s a difference between hardware people and software people).

Darcy Moore wrote a great series of posts on this topic back in May. I encourage you to read his posts on the topic as he reached out to hundreds of people to generate his lists.