Project Management Training: Prince2, Agile, Scrum

Prince 2 is quite dated, and not really used outside of large organisations, but is a good introduction to PM methodology and core practices. Take an introductory course if you fancy learning the principles.

Agile methodology is highly relevant for IT, is a bit more modern, but tends to break down if not strictly applied - very useful to understand, and quite 'trendy' but not many of the organisations that say they work agile truly are.

Scrum is an agile subset which has highly defined roles, and is very effective, training as a Scrum master or product owner is a good way to showcase your thinking and requires minimal training.

Kanban is another methodology to acquaint yourself with and it's a bit less strict that the above, but it's easy to track and get good results with. The most important things you need as a Project manager are the ability to think ahead, communicate effectively, and cover your arse.

And as a softwaretester we all know project managers are wankers that just lie to make them look good to the product owner: ie cover their arses.

Edit*

Unless the project manager has worked as a tester himself and knows the ropes.