If you want to use SmartyPants with WordPress, you can grab this: Textile 2.0.2 and SmartyPants-PHP plugins.
Basically, the SmartyPants plugin is just a wrapper for the SmartyPants-PHP distro, and if you want to use it without Textile 2 you’ll need to add your own add_filter calls to the file. But if you enable Textile 2 — even if you don’t use any of the Textile 2 features — it will SmartyPants your text. If you don’t enable SmartyPants, the Textile 2 plugin uses wptexturize().
This is actually a different implementation of Textile 2 that more closely mirrors the MT version by Brad Choate, not a hacked-up version of the one that ships with WP.
