From B2evolution

The Texturize Plugin will replace standard and double quotes with typographic quotes were appropriate (“” to ""). It will also perform the following replacements:

• --- to — (entity —)
• -- to – (entity –)
• ... to … (entity …)

[edit] Location

The Texturize Plugin gets shipped with b2evolution and can be found in /blogs/plugins/_texturize.plugin.php.