I agree with what drew said. Limiting posting would be a downer.
But this is not a very big problem. I think new members are sent a PM by default, to read the rules and Guide before posting. So a more strict step is not necessary. I think the main problem for newbies, is the huge lot of things they can access in the forum. I mean... they don't have a simple interface, etc. - you can play around with so much in your forum-board interface, that they find it too intimidating to learn to search.
And then, changing the default search-period from "30 days" to "any date" is not good too, because most of us want to search only in last week, actually.

So if it is "Search in any date" by default, that will totally flood the newbie with results. Again, it gets intimidating to look thru all of that, so they take the easy way out and directly post their repeated questions.
No, as of now no action is needed. Just wait until the upgrade to IPB2 is finished. Then, the new member when sent a PM (about the rules and guide and searching and introducing himself) - will see a big-coloured message at the top of the board. So he cannot possibly forget (or not notice) the PM. Patience, I think is needed.

The entire frustration will be solved (or helped to a large extent) once the upgrade is done. It will solve itself, don't do anything about it.
If any of you feel irritated with repeated questions, the best thing you can do about it, is to *NOT* reply to it. After some days, they'll get round to search. Shouting at someone for not having read old topics only just deviates from the friendly atmosphere here. You either help the person, or don't reply to a question (if it irritates you). That's all.