The calls for talks for D3 #5 are out, they say...
"Because the event is for the community and by the community we are currently looking for speakers who would like to present. You don't need to have spoken before, but do want to share your experiences and knowledge of .NET with other developers."
So, if you've got something interesting to say, why not give it a go?
Source: DeveloperDeveloperDeveloper! Day