I picked up two softshell crabs this weekend and had the fishmarket clean them. I have never made them before, but they looked really good in a recent recipe I saw in Gourmet or Bon Appetit -- however I can't find it on Epicurious now. Anyway, it was pretty easy -- soak the cleaned crabs in buttermilk for one hour, dredge in cornmeal mixed with a little flour, salt and cayenne. Rather than deepfrying in peanut oil, I fried them in about an inch of canola oil in a small skillet. Then drizzle with browned butter with lemon juice mixed in.
They were absolutely amazing, and very gratifying to have such success the first time. I highly recommend trying these little guys while they're in season.