Information on pre-order statistics is available online at VGstats. While those don't include the online pre-orders (so far as I know), they do provide a pretty good indicator of the overall pattern in pre-orders.
Based upon that, Wave 1 today is already TWICE the size of any of the waves yesterday.
Assuming they can keep pace with that, that's a very good sign for September pre-orders. Based upon yesterday's pace, we would expect to get in on Thursday, but DOUBLING the rate at which they're letting people in means we have at least a chance of getting in later today.
Think of it this way:
September 1st: There are ~120,000 people ahead of you in line.
September 30th: There are ~240,000 people ahead of you in line.
Day 1 invites were roughly 50,000 per wave. First wave of Day 2 had roughly 100,000.
Make of that what you will.