The Spider Cut is not really a cut - it's more of a flourish. To see a video tutorial (no speaking) go to this site: http://www.youtube.com/watch?v=SLtkhERny0U
(this is NOT by me)
I give credit to Mikkel Samuelsen, and twin brothers Dan and Dave Buck for this.
I will show step by step photos and explanations. Good luck!
Hint: It's easier than it looks (not saying too much but still...)
Step 1: Grip
How you hold the deck to start.
Picture 1: Ensure you hold the deck EXACTLY in this position.
Picture 2: You should be able to do that.
Picture 3: The starting grip.
By the way, look for cards that fit your hands. It's much easier for learning. When you are done, you can use larger cards (like title pic).