There's a cool new tutorial on creativecow.net about 32bpc comping in AE7. Check it out, as it quickly and effectively demonstrates the fundamental idea behind HDR and a couple of things is does really well.
I just have a couple of technical notes on Andrew's tutorial. Andrew shows how to extract an HDR from a camera raw file, and he does this by taking Exposure, Brightness, and Contrast down to their lowest settings. This is fine for Exposure and Brightness, but you want to set Contrast to zero, along with Shadows, as we discussed here.
The second note is that Andrew keeps reaching for the Gaussian Blur effect, but we know better, right?
Anyway, it's still a great intro to float, and it's cool to see others taking up the evangelism cause.