Mmm. I am dying to tell, too, but am just waiting until I have all the information. Actually, it's an open secret in my office, as I've told almost everyone except my two supervisors and the uber-head-honcho. I work in higher ed, so my colleagues are all supportive, but I haven't always had the best relationship with my supervisors, so there is some concern that they'll take the opportunity to give me the boot.
On the other hand, if they give me the boot after I give notice, won't that look like retaliation? My position is covered by a bargaining unit agreement, so I have some backup. I have a performance review coming up in April, so I'm planning to try to hold out until then - and give them four months' notice, with plenty of time to make sure that they can find the best candidate to replace me and that I have plenty of time to prepare for the transition and train him or her.
Maybe it's crazy. But, I'm not very good at keeping my mouth shut, and I've already been holding my tongue longer than I ever thought possible. And, worst case scenario, at least I don't have a resume to worry about for a little while - I can make my rent by waiting tables for a few months, if need be.
I can't imagine a scenario where your colleagues would be able to do anything to sabotage you. That sounds like a terrible environment to be working in - glad that you're getting out.