Is there any valid source for the claim that Voltaire' house has been used by the Bible Society? I heard this many times, but I've never read a valid source for it.
Apparently it is not true:
While the exact details may not match the most popular versions of this story - the house being used (ie on an on-going basis) by an actual Bible Society - there is evidence of a kernel of truth from which this story came.
This evidence is found in the wikipedia article on Voltaire's* home in Geneva from 1755 - 1760 "Les Délices" (See in particular the paragraph:"After Voltaire"), which cites an article in reference to the question, by Rev. W. Acworth (1836) from "The Missionary Register." (mouseover reference 6 - which contains a clickable link to the full article in GoogleBooks.)
The article verifies some of the details used to the 'refute' the original story (that this home was never used or owned by a Bible Society per se and is currently being used as a museum dedicated to Voltaire's life and works). This source asserts that the home WAS owned by the President of the Evangelical society of Geneva and used during this period as a repository for Bibles:
*a nom-de-plume; real name: François-Marie Arouet
I don't think we can determine the truth about one of Voltaire's houses being used to print Bibles, only what sort of website considers it a fact. Here is a reference that quotes wiki and explains that there was a second house -- actually in Geneva. Feel free to believe or disbelieve this version, as you prefer, since this site doesn't have any references.
The following article, by a non-believer, is mentioned at the link above:
http://www.nzarh.org.nz/journal/2004v77n1aut.pdf (see toc for article about Voltaire's house)
This appears to be somewhat carefully researched, although I didn't check his references. If it is correct, none of Voltaire's houses were used by Bible societies. The article suggests the story may have originated due to a hotel Gibbon, from which many Bibles were sold, being mentioned in a book in the same sentence as Voltaire.