Where is a site that one can find the P/E ratio of foreign stock
indexes? It is easy to find p/e ratios of domestic stocks and even
domestic indexes, like the s&p. But I can't seem to find the foreign listings.

Can you clarify somewhat?  The term 'foreign stock indexes' is pretty
broad;  a specific list of countries you're interested in would help.

Also,  be aware that earnings are not reported the same across the US
and Europe,  let alone Asian nations, and hence direct comparisions
may not be valid (comparing apples and oranges).