how do i allow <span> tags in posts

[wahooka]

hi-

how can i allow <span> tags in forum posts?

like from my newly imported forum i have:

<span class="greenbold">some text</span>

but right now the < > tags are being replaces with the &lt; type ones... so instead of actually displaying the style (green bold), it outputs the tags like this:
<span class="greenbold">some text</span>

i would like to allow <span> tags only for admins but if thats not possible i'll settle for allowing it for everyone.

thanks