They are called smilies, here is the page with all of them:
http://www.yorkietalk.com/forums/new...te=1&p=126369#
Just use the : rose : (without the space inbetween, when you want it to show as a rose smiley. And you can go here to edit your signature:
http://www.yorkietalk.com/forums/pro...=editsignature