While researching for my no elastic panties tutorial (I wanted to see what was already available!), I fond this great website called the Pattern School, mainly for making swimwear, but it also has a section with pregnancy size charts!
It's quite technical but easy to understand, and it has all the info if you want to make your own swimwear, or even some for your husband or child. There's even a section for "lazy people" where you can enter your own measurements or find "lazy" patterns. It is a great reference, and I'm stoked there is a size chart for maternity wear!
Another cool blog I've been checking out is Makeshift. The author is on a one year mission to wear only what she can make (she even made her shoes!). She's a few days away from completion, but it is so inspiring! She makes coooolll clothes. Here are a couple of my favorites.