For topics and forums which require all posts/topics to be approved, it's good to have a page that informs them that their posts or topics need to be first approved by a moderator before it is visible. It should be shown right after the user clicks on the Submit button for their new posts/topics. vBulletin has this feature, I don't see why IPB should neglect it. This would avoid any confusion with members asking where their posts/topics went and cuts down on duplicate posts/topics.

I think there's a short redirect screen informing them that a moderator must approve the topic/post first, although members often won't notice it. The best solution IMO is to just show the invisible post to the post owner as well as the moderators.

yes, but you have to be very quick to notice it.

It looks very similar to the normal redirect page...its just a little bit more text.

Fast workaround: find this part in the language editor and set the color to red (or something more noticable).

You know there's already a mod for it though? (Made by _Cy_) You could do a search on IPSB.