The answer to your question is yes, but it get can be a little complicated. The Hague Conference on Private International Law is an organization to "work for the progressive
unification of the rules of private international law." What this means is that it is like neutral third party - However, no nation needs to reconize the rulings of another. So, even though it is possible to sue individuals from the United States who are from another country, even if you win, you have no means to collect on the judgement unless they enter US soil.
However, there are a number of nations who have agreed to work with the conference so that mutual agreements can be made as to how to procede with a case against another in that country, how to serve court papers to an individual within that specific country, ect. So, suing an individual from a different nation would be much easier if they were one of the 65 five states that have agreed to abide by this relationship. Currently the United States is one of the nations in this organization.
The other nations are:
Albania Argentina Australia Austria Belarus Belgium Bosnia and Herzegovina Brazil Bulgaria Canada Chile China Croatia Cyprus Czech Republic Denmark Egypt Estonia Finland France Georgia Germany Greece Hungary Iceland Ireland Israel Italy Japan Jordan Latvia Lithuania Luxembourg Netherlands New Zealand Norway Panama Peru Poland Portugal Republic of Korea Romania Russian Federation Serbia and Montenegro Slovak Republic Slovenia South Africa Spain Sri Lanka Suriname Sweden Switzerland the former Yugoslav Republic of Macedonia Turkey Ukraine United Kingdom of Great Britain and Northern Ireland United States of America Uruguay Venezuela
list taken from:
So, to answer your question, the best way to sue an individual from another country is to find a private international attorney. He/She would be familiar with the protocals called for by the conference and all othe other details that would come up.
Hope this helps.