This isn't really a programmer-specific question, but I'm not sure of a more appropriate place, and I think the users of this site are best able to answer the question in the context of programmers.

Relocating to the US seems fairly common in the programming industry. I live in the UK, and maybe one day, I might do it too.

So, if that day comes - how would you go about comparing job offers? Benefits are fairly easy to compare, but given the differences in cost of living, how would you go about comparing salaries and the quality of living you'll have?

In a country where the cost of living is lower, you might be able to accept a lower salary (based on exchange rate) and still have the same quality of living. But what can you do to ensure this? In some cases, you may even take a "pay rise" in terms of exchange rate, but end up far worse off.

How can you compare job offers across different countries to get an idea of the salary you would need in order to not feel you've gone "backwards"?