Birth doulas primarily provide emotional and physical support during labor, however they can also be a source of reliable information during pregnancy. See this link from Doulas of North America's website http://www.dona.org/mothers/why_use_a_doula.php
There are also postpartum doulas which provide support to you after your birth (helping with other children, cooking, household chores, errands, etc).
Doulas of North America International (DONA International) is the main certifying organization for doulas. It is the largest and most well supported doula organization in the world.
Also, on the link above in the left hand margin there is a search you can use to find a doula in your area.
Good luck!
