To allow guests to post on your forum, you will need to edit your forum permissions. To do this, go to your administration panel(the link located usually on the bottom (footer) of your forum/website)

Click the General tab, then "Categories & Forums" located under Forum. For each forum, click the permissions icon, for each forum, and modify the permissions. Make sure Guest is ticked on the Write & Reply section of the permissions,

Like this (where my cursor is):



Save, and guests will be able to post. In the future, if you wish to have the same permissions for a new forum, simply select an existing forum that has the permissions you want to use for the "Copy forum permissions" presets drop-down list.

Hope this helps

- Ares/pimentel2

shrizzle: please avoid posting just one smiley as a post as this can be considered as spam. (Not to mention that it's not a nice smiley)

I hope the information above helps. Well done, pimentel2!