Scrum is one of the methods of doing Agile work… here’s the basis: www.agilemanifesto.org – It’s used mainly in project management and software development these days as a way of getting things done faster and better than old methods (such as "waterfall", where you would plan, plan, plan, plan for a long period of time, then build… and hope your plan from 6 months or 2 years ago was still relevant.)
Doing ‘Agile’ project management has been popular for the past 8-10 years, but it’s picking up steam a lot more these days with the desire (from business) to deliver what customers want as quick as possible – AND react to change much faster than before.
The principals are simple, but you have to have committed people, otherwise people will still row in different directions :)