This is a complicated issue full of nuances and conditions which can only be dealt with by scholars and jurists.
The general principle seems to be that a non-Muslim cannot inherit from a Muslim, but in certains circumstances, a Muslim can inherit from a non-Muslim.
One nuance is the fine line between an inheritance and a gift upon death (a bequest)
Another consideration for some is the location of the event. Whether there is Sharia Law in effect in that country. An interesting situation, in this day of global travel, would be if the deceased were in a Muslim country and the beneficiaries were in a secular country.
So on the surface it is very simple, but go just slightly beneath the surface, and it becomes a matter of jurisprudence.
A Muslim cannot inherit from a non-Muslim. And vice-versa.
Notwithstanding the above, another opinion states, this only applies only to countries that have Sharia law, and in his opinion, the secular laws of non Muslim countries also apply to Muslims when there is no Sharia Law.
http://www.islamonline.net/servlet/...h-Ask_Scholar/FatwaE/FatwaE&cid=1119503545320
A third website makes a distinction between an
inheritance of property and a
bequest of money. In that view, the inheritance of property would be disallowed, but the bequest of money would be alright.
http://qa.**************/issue_view.asp?HD=1&ID=3296&CATE=201
All of the above is according to my understanding.
I can see why very few Muslims would want to post on this question. There are numerous other rules on the issue of inheritance in the Q'uran.