Hello !
I have put back Special:Disambiguations in 1.5, it was broke since the schema change. It works in a different way now, hopefully it will be easier to maintain disambiguations.
Let's see how things worked before 1.5:
When someone created a disambiguation page, he had to put the {{disambig}} template then edit a page listing all disambiguation page. Special:Disambiguations will then find the pages pointing to an article in that big page list. Some problems happened: people often forgot to add or remove the disambiguation page in the list. It took a long time to generate.
New system (commited to cvs and live on WikiMedia servers):
A page need to be configured as being a disambiguation marker. This is done by editing [[MediaWiki:Disambiguationspage]]. Every page linking to that marker will be considered by Special:Disambiguations as a disambiguation page. The output is then a concatenation of "whatlinks here".
How can it be set on wikipedia ?
Most projects, if not all, use a template to mark disambiguation pages as such. A sysop should then edit [[MediaWiki:Disambiguation]] and replace the text there by the article name used to flag disambiguation pages.
I asked sysops on FR,ES and EN to make the change: http://en.wikipedia.org/wiki/MediaWiki:Disambiguationspage http://es.wikipedia.org/wiki/MediaWiki:Disambiguationspage http://fr.wikipedia.org/wiki/MediaWiki:Disambiguationspage
The same change should be made on all projects to correctly generate the disambiguation list.
IMPORTANT: [[Special:Disambiguations]] uses a cache. Once a sysop changed the [[MW:]] message, you will have to wait for the page to be regenerated. Developers in #wikimedia-tech will be able to regenerate "on demand" so you can check if everything is correct.
Note for developers to regen enwiki: php maintenance/updateSpecialPages.php enwiki --only=Disambiguations
Please spread the word, specially for small wikis.
cheers,