The waiting period prior to receiving a response varies with your position in the queue of interviews. If you were the final interview, you may receive a response rather quickly; however, if you were the first of the interviews, you may need to wait several weeks.

Rejection: Typically arrives by snail mail or by email.
Neutral or no news: You are still in consideration, but not the first choice.
Offer: Typically given over the phone.

If you receive a verbal offer, be gracious and enthusiastic, but do not accept the offer on the spot even if you are planning to do so. Request the offer in writing and time to consider it, especially if you are waiting to hear from other potential employers.

Do your homework

The first step in any negotiation is to be prepared to negotiate. Like in all other aspects of the interview process, do your homework. Know that most everything is negotiable, to some degree or another, including salary, start-up package, space, relocation, support, etc.

Resources

Ask For It: How Women Can Use the Power of Negotiation to Get What They Really Want - Linda Babcock (Postdoctoral Career Resource Library)
Academic Scientists at Work: Negotiating a Faculty Position - Jeremy M. Boss & Susan H. Eckert
Evaluating Job Offers and Negotiating - American Psychological Association
Go Ahead, Haggle - Rebecca A. Bryant & Amber Marks
Negotiating a Better Deal - Julie Miller Vick & Mary Morris Heiberger
On the Job Market? Don't Sell Yourself Short, Even Now - Audrey Williams June
The Etiquette of Accepting a Job Offer - David D. Perlmutter
Academic Job Search: Negotiations - University of Washington Center for Career Services

Salary data

Chronicle Data Salary Survey - The Chronicle of Higher Education