ITIL stands for Information Technology Infrastructure Library and is a framework for service management. There are multiple layers of training/certification, the first of which is ITIL Foundation. ITIL Foundation is a two and a three day course that culminates with a 40 question multiple choice exam on what is now the five areas of service management, based on ITIL v3: Service Strategy, Service Design, Service Transition, Service Operation, Continual Service Improvement.
You can find out more at the Official ITIL Web Site. Fees for training may vary among providers, so your best bet is to canvas your region for this information.
The entry-level training/certification, ITIL Foundation will fit the needs of most people in IT, unless you are directly involved in service management. It will provide you with a basic understanding of the service lifecycle. The main advantage of this, as well as other frameworks and methodologies is that they give you a window into and get you thinking about the different interactions required to maximize the potential for successful service/project delivery within IT.
ITIL is the preferred framework of processes for managing the operational/production/delivery side of IT, as distinct from the development/solutions side.