Where can I find an example implementation of the "New Import Hooks" described in PEP 302?
I would like to implement a custom finder and loader in the most forward compatible way possible. In other words, the implementation should work in python 2.x and 3.x.
You can find thousands of open-source examples e.g. with a google code search (can't get the URL right for a link with SO's markup, maybe it's too long, so here it is...):
http://www.google.com/codesearch?hl=en&lr=&q="imp.find_module"+"imp.load_module"&sbtn=Search
Edit: as the questioner clarified he's looking for example of implementation, not use, a betted URL for the search is:
http://www.google.com/codesearch?hl=en&sa=N&q="path_hooks"++lang:python&ct=rr&cs_r=lang:python
One readable example (though NOT suitable for production use, as the reddit discussion points out!) is urlimport.
As for supporting Python 2 and Python 3 at the same time, that sounds ambitious -- I don't know of any existing import hook which claims to. In your shoes, I'd start with offering full support for Python 2.6, then once that's working (and has a good battery of tests and makes nary a peep with the -3 switch), I'd 2to3 the sources and see if anything breaks (if so, find out why, fix the 2.6 sources, iterate).
Maybe this could help:
http://journal.thobe.org/2008/07/simple-stuff-with-import-hooks-in.html