What structure does anyone suggest for multilingual pages in development versions?

I have successfully got basic language links of the type [[fr:My French Main Page]] working, (thanks jdd, 22/03/2006), by adding rows into the interwiki table with values "fr" and "http://localhost/fr/mediawiki-1.5.6/index.php/$1". Now, when I add [[fr:My French Main Page]] to the Main Page of the English version, I get an entry in the "other languages" side bar which looks like "Francais" but which links to http://localhost/mediawiki-1.5.6/index.php/Main_Page".

For production type pages the structure seems clear, en -> mywiki.com or en.mywiki.com fr -> fr.mywiki.com nl ->nl.mywiki.com etc.

But what does it usually look like in development?

en -> localhost/mywiki/index.php fr -> localhost/fr/index.php or localhost/index.php/fr or what??

And then is there any easy way to make the settings in the wikilink directory the same for development and production versions?

Thanks!