Okay I've recently worked out how to do this.
So if there's a smiley you like form a different forum or website - post it in this thread and I'll add it to the forums smiley list.
here are the ones I added yesterday from my food forum:
Any new smileys will be useable simply by putting the 2 dot thingy (actual name currently escapes me) either side of the name.
so for example to get this
you type : whistle: without the space.
So with an added space the above smileys look like this:
: thumb:
: noidea:
: whistle:
: nana2:
: sausage:
Any smileys I add will be listed with the text shortcut as well as the name they are called in the 'more smileys' list on the left side of the post screen.
Have fun