A few days ago, Metal Gear 4 Associate Producer, Ryan Payton, announced that Metal Gear Solid is going as planned, and will be out on the shelves in Q2. The game is actually done, you can play it start to finish, and all that's left is brushing up on minor bugs and making an intro movie trailer.
Ryan is convinced there will be no delays, and we hope he's right. The PS3 version will also be available in Q2, but a fixed date is not set yet. The game will not be launched in one day worldwide, so expect different launch days for different time zones.
You can read more on the official website.