Not completely, but find some kind of solution that works for you while you're going through this transition. What's working well for me right now is this:

• I scan through my blackberry in the morning to see if there is anything that appears to be urgent, but I don't turn on email on my computer
• I get to work and leave my blackberry in the kitchen, and look at it only when I get up for a coffee/tea break or lunch.
• I spend an hour or so in the afternoon replying to email, and I try very hard to stick with the time limit and not lose focus
• I allow for free time with email and Facebook in the early evening
• I simply tell people I'm working on a project for the next 8 weeks. It's not forever and most people respect that you're focused. It even creates some curiosity.

Remember, you don't have to always be available by phone, email, text messages etc.