Any advice on personal pension?

I'd want to know if there are people who can tell me about personal pension plans that fits to someone who work abroad long, and who might not be covered well by the company benefit. I could look into German bank programs (where I currently reside), but I rather prefer something targetted for international customers that provides English contract and documents.
I want to know if:
- my residence country matters to the plan;
- advantage & disadvantage among various personal pension plans;
- what is the criteria to choose?

Thank you for your help!!

Miyak