[kh99]

If you had your options in the variable $options, you could use this:

if ($options & $vbulletin->bf_misc_forumoptions['allowposting'])
{
   // Forum Open
}
else
{
   // Forum closed
}

That's assuming you have $vbulletin available. If not, the value is actually 2, so you could use if ($options & 2) instead.