In case all of a sudden you start seeing strange characters instead of an apostrophe-there is a good chance it can easily be fixed by a simple tweak to your wp-config file.

In the move for global blog domination, WordPress began acknowledging character encoding for different languages- this excellent article will give you the answers you need to your broken WordPress install:

WordPress Charset Encoding Problem After Upgrading to Version 2.2 » My Digital Life
WordPress blogs that upgraded to WordPress version 2.2 may encounter strange character set (charset) encoding problem where several characters especially apostrophes (’), quotation marks (”), and hyphens or dashes (—) are displayed as strange characters such as ’ or simply as question marks (?) when the posts are output to web pages. As you have probably suspected, the issue is caused by character encoding method used by WordPress 2.2 which supports setting of database collation and character set in WordPress config file.

We’ve been dealing with it sporadically on our server- and know how to fix it chop-chop. Just give us a call.