This is not a duplicate of this question.
I would like to know what the differences in their characteristics are. I'm thinking for example about their majority carriers (electrons for NPN, holes for PNP). Does that mean that NPNs are faster?
This question is far far far too well answered on the web to be sensibly answered here. This really is a "Google can tell you better than we can" type question.
Excellent examples include.
Electronics tutorials- transistors.
and 6 other transistor related pages.
Much more ...