Here is the answer from my end.
Internal training - This happens when the, Trainers are on the company payrolls conduct the training programs for the employees as when as required. e.g induction programs conduted by HR & Training depts in most companies. Here trainers are the employees of the company.
External training - In this process, an external trainer from a training company or a freelance trainer is invited to conduct a 1or2 day workshop for the employees. this is external training.
Let me know if you require more info.
18th March 2010 From India, Hyderabad