Subject: Other worlds where H2S serves in place of H20?

I saw a show on NOVA a few nights ago about bacteria that use
hydrogen sulfide in place of water for (what I perceived as) 
their endpoint of electron transport.
This idea fascinated me.. Is it possible that on distant worlds
there could be conditions favoring H2S oceans, icebergs, 
rainstorms and dark sulfurous clouds? I seem to recall that one 
of the Jovian moons had a lot of sulfur on it. How different 
would such an environment have to be from the Earth to allow H2S 
to function in the role of water?

Thanks for providing this service!
- J.

Re: Other worlds where H2S serves in place of H20?