The purpose of an elevator pitch is give a succint, compelling presentation for why your project is worthwhile. The presentation must be able to be transmitted by word of mouth in a sentence or two. The image you should have is that of having 30 seconds (the length of an elevator ride) convince a very busy person, who knows nothing about your project, to take interest in it and give it support.
The key is to define what you've done from the perespective of the client, and clearly define the value that you bring, and why what you offer is unique.
To create your elevator pitch, begin by filling in the blanks in the following template:
OUR PROJECT IS
FOR [target customer/client/user]
WHO [statement of the client's need or opportunity]
THE [project name] IS A [category of thing it is]
THAT [statement of key benefit -- that is, the compelling reason to use or buy]
UNLIKE [primary competitive alternative]
OUR WEB SERVICE [statement of primary differentiation]
In order to do this:
Don't underestimate how difficult it is to create a good elevator pitch.
On Thursday, we will ask one person from each group to stand up and deliver an elevator pitch for the project.
Note: This template comes from Crossing the Chasm, by Geoffrey Moore.