Instructor rating
Hi there sainty.
As far as the UK is concerned if you want to get paid for instructing then you have a long and expensive road ahead. First you are going to have to do the ATPL ground exams, get 150 hours total, 100 P1 before getting a comercial pilots licence you'll need 200 hours to get it issued. Then you'll need to do an FI rating before you can instruct. Best thing to do is read Lasors as that will tell you exactly what requirements you are going to need. Don't know the US requirements but i'd hazard a guess they are similar. Can't comment on pay comparisons but in the UK it varies, but generally they aren't that good.
Hope that helps,
Han.