Once again.
Play.com will have copies, But do not have the ability to distribute copies until a date specified by the publisher. If they do so, They will be in breach of contract and fined.
They aren't going to take a fine (last I heard, £30,000) happily.
They're allowed to dispatch to guarantee Release Day arrival, so Thursday is likely.
Play.com do not debit you until the order is Dispatched.
Retailers like Wal-mart, who are huge moneymaking machines can risk the fines.
You'll also see retailers like Wal-mart doing Release Day specials.
For example. In the UK, MW2 and Fifa 10 were £25 on release day because the massive sales they have will offset the lesser profit per sale.
AvP isn't on that scale of release so don't expect that however.
Alpha Defekt:
AvP is street dated. 16th in the US. 19th in UK.
Release date = Street Day.