That looks to me more like a whitish powdery dusting typical of Powdery Mildew. If this white "stuff" rubs off and is a dusty material that is more than likely what it is.
Many people have had good success eliminating that with sprays of either a 50/50 mix of fat free milk and water or 1 teaspoon of baking soda (some people have better success adding a drop or 4 of oil) in 1 quart of water, eithe of these sprayed every 5 to 7 days on affected plants.

Here is a link that might be useful: About Powdery Mildew

Or is it the normal silver coloration that many squash leaves acquire?

We need a larger image to know just which it might be.

I'm pretty sure it isn't powdery mildew. I had it last year and it just sucks. I'm just freaking out because I haven't had a squash plant look like that before. Maybe it is just normal markings and i'm overreacting but I am pretty sure its not powdery mildew. I'm sorry but I dont know how to make a bigger picture I'm a complete noob at forums =P

Post another image, one where you're closer to the leaf.