apostrophe in PHP code posting

My blog is about web development so I’m sharing a lot of php codes that I write, but the apostrophe is changing on me as I publish the article.

Example article here:

http://www.crankberryblog.com/2009/php-image-verification-aka-captcha-basic

So I do my code in notepad in which I use ‘ and it copies perfectly fine into the writing box but it turns out ’ (I’m not sure if they’ll show up), which if you copy and paste the final code back into word it won’t work.

I’m always posting my code in HTML edit format and the charset is the default one by wordpress UTF-8. Anybody have any ideas what I made need to edit?