My favorite Mexican expat travel bloggers at Two Expats Mexico recently published a couple of great articles about tax issues for those of you who live in another country.
The first covers tax reporting requirements for US citizens who have foreign bank accounts.
What Americans With Foreign Bank Accounts Should Know About Annual Reporting Requirements
The second covers the extremely valuable foreign earned income exclusion. So long as you are an American citizen living full time in another country (defined by being outside the USA 330 days or more in a calandar year) you are exempt from US income tax on the first $107K of your income.