In addition, doulas.com also has many different specialties listed in a drop down menu to find providers outside of doulas, including midwifery services, nutrition counseling, yoga and much more. Both mamaviews.com and doulas.com have a feature to search for lactation consultants, too.
Doulamatch.net offers the option to search for a doula by your due date availability and doulas.com has an availability calendar on each doula's profile. With doulamatch.net you can view complete profiles that include the experience level, price range, and certifications of doulas as well as read reviews posted by actual clients.
Mamaviews.com has a rating system tied in with their client reviews that uses a number scale which has ratings for categories that include birth education, birth plan support, early labor support, active labor support, birthing support, dependability, and breastfeeding support. They then average these categories for an overall score.
The good news is that the internet can help you do some of your homework when it comes to selecting the doula that is the right fit for you. Even better is that most doulas will offer a free consultation to see if and it gives you the opportunity to make sure they really are the best doula for you!