How do I view emoji in Google Chrome on OS X (prior to 10.7)?
If they are using real Unicode emoji, you cannot see them without the Apple Color Emoji font, which only works in 10.7, or possibly by downloading and installing a black/white font that has them, like Symbola or Quivira.

Unicode emoji were only standardized in October of 2010 and I think there are various apps which may not recognize them anyway.  Here is Timothy's test using the Symbola font in 10.6