I just finished a large chunk of work on my own full-text search plugin for Joomla.

It works in conjunction with Sphinx to index and search Joomla content "the right way." (i.e. not using basic LIKE statements)

Edit (Feb. 27, 2010): I just released a beta version of this plugin here: Joomla Sphinx Search Plugin

Joomla has been notorious for not being able to sort search results by relevancy and really, it's not very fast either.

Sphinx allows for full-text searching on any type of database table (so you're not forced to use MyISAM), and can even work with PostgreSQL (which Joomla unfortunately doesn't support.) It can handle a number of advanced features like:

• Wildcard searching
• English word stems ('dogs' => 'dog')
• Stopwords ( so that words like 'the' don't get searched)
• Equivilent word matching ( cpp = c++ = cplusplus )
• Live index updates ( although my plugin does this manually )

The project I'm working on is a three part system, including:

• Search plugin – to take the search terms and call the Sphinx search daemon.
• Content plugin – to update the Sphinx index when a new article has been written or updated.
• Admin Component – to help maintain, help configure,  and assist in setup of the index.

I don't know when this project will be released in beta, but hopefully by next week I can get something cobbled together. Let me know (Email me) if you're interested because I want this project to be as usable a possible and would very much appreciate the input.