Below you will see a chart that gives approximate conversion of your "raw" points scores for the TOEFL speaking and writing sections into the actual section scores used by ETS to generate points scores out of 30.
This answers the common tricky questions like how 6 speaking tasks of 4 points each can total up to a score out of 30...
Note that these are approximates only. I took them from Nancy Gallagher's DELTA's Key to the Next Generation TOEFL Test - Six Practice Tests for the iBT. I generally find the DELTA information and practice tasks very reliable, which is why I've gone with their guidelines here.
One of my private TOEFL students got a score of 27 on her first try at the writing section. I'm scratching my head trying to work out exactly what that meant in terms of scores out of 5 in each of the writing tasks...