What is ERP?
ERP stands for "Enterprise Resource Planning" and is a series of computer packages/modules which link together to provide support for the day to day running of a business. A small company may invest in a few modules (say payroll and accounts) and a larger company perhaps would need more (for example a stock keeping/ordering package). Typically the modules run from a common database, with updates on one package impacting others. Training in the operation of the new software must be given and the company is tied to one supplier for all modules.
Rather than having to learn and pay for developments in different supplier software for Payroll, inventory, Accounting, Inventory, HR, and other core areas, a proper ERP software allows you to grow when you need to, and run off one system but with the ability to communicate to more mainstream programs if needed. Its usually not cloud based as most companies are aware of the importance of onsite accounting and inventory programs (security of data and speed) and the size of the system is usually something preferred to have onsite.
An ERP system that is able to be customized is thought to be best as every business is different and some of the larger very expensive ERP software systems are just too extensive or off the mark for small to medium Businesses.
BEST YOU-TUBE VIDEO EXPLANATION BELOW:
http://www.youtube.com/watch?v=t2n1zi28Bec shows a fantastic 2 minute explanation, this its a great short video on What is ERP?