Can anyone recommend a good (preferably add free) message board for an online Dark Heresy game I am spinning up?

TIA.

I have used both rpol.net and darkreign40k.com. I prefer rpol.net, though.

I will keep an eye out for your DH adventure.

Myth-weavers is also a good site. I run a Rogue trader game over there and the boards are made just for pbp games with many useful functions and access to a wiki. Also while not built for it RPGnet has a very active pbp board with DH based games not being too rare.