Am 19.03.2011 um 09:21 schrieb Mojca Miklavec:

If font supports the emoticons in the first place, one could also
define ligatures to create them automatically with
   :-)
etc. But personally I would prefer to use \externalfigure and find
some really nice images out there as opposed to using whatever limited
set of black-and-white images a font provides.

You can also do a lot with symbol fonts [1]:

\startTEXpage[offset=5mm]
\definedfont[file:Dingbats2SamplerOT at 80pt]%
\dontleavehmode\hsmash{\yellow\fontchar{d.alt001}}\hsmash{\orange\fontchar{d.alt002}}\fontchar{d}
\stopTEXpage

[1] http://www.ffdingbatsfont.com/

Wolfgang