An Introduction to Scrum (a type of Agile Development)

From http://www.agiletroop.com/product/life-cycle-of-scrum/
Here is a more detailed infographic.

At a high level

while(!isProjectFinished){ Plan Build Test Review }

Iterative
Involve the customer in what is delivered, when.
Continuously respond to customers changing needs, changing requirements.
Continuously deliver working partial product. Confirms customer understanding as well as developer understanding.
Continual reporting on effectiveness of team, progress on development, cost.
Agile in general is good for managing customers expectations (Arnold's experience).

Product Owner: Knows what the product is supposed to do. They have the product vision, and are responsible for communicating this clearly to the Team. In Scrum this vision is represented as a Product Backlog This is a prioritized list of User Stories (= Features = Requirements) that they would like to see in the system.
Example Product Backlog

A User Story is essentially an atomic feature from the perspective of a user. It usually captures a single interaction with the system. Basically, a User Story is a requirement written in the language of the users. Users should be able to test it to say whether the feature is implemented in the system or not. This leads to User Acceptance Testing. In Scrum, the template looks like:
Scrum Master: Serves both the Product Owner and the Team, knows the Scrum process, ensures that the process is taking place. Basically, they make sure everyone is following the above diagram. For example, making sure that the Burn Down Chart is created and maintained.
Team: Designs and builds what the Product Owner wants.
- Analysts
- Designers
- Developers
- Testers
- ...

A code sprint is one time throught the loop above.

Sprint Planning: A meeting with PO, SM and Team. Take highest priority user stories and create the Sprint Backlog.
Sprint (1-3 weeks): Team works on delivering the Sprint Backlog. They architect, code, test, document etc. They also hold Daily Scrum Meeting.
Daily Scrum Meeting: A meeting with SM and Team. 15 Minute standup meeting, each team member says
Sprint Review: A meeting with PO, SM and Team. Show off product to PO. Acceptance test as well as discussion of Scrum Process improvement.
Sprint Retrospective (more later)