Two days before the official launch of the iPhone 4S, Apple has made the brand new iOS 5 available for download. According to Apple, there are over 200 new features in the new OS.

The feature that seems to be getting the most buzz is the new notification center. This new feature organizes and houses all the notifications from your apps into one neat little menu. When you are using any app, new notifications will no longer pop up in the middle of your screen and disrupt your activities, but will now appear discreetly at the top of your screen.

You can swipe down on the screen at any time to access the full notification menu and swipe any individual notification inside the menu to immediately go to that particular app. In all, it’s much more seamless than the previous notification style.

iOS 5 also adds iMessage, the messaging service specifically for iOS 5 users. It will allow you to send unlimited texts to iPhone users via Wi-Fi or 3G.

Reminders are now integrated into the notifications and are location-based. That means you could get a reminder that says “Don’t forget to buy milk” as soon as you pull into the grocery.

Like promised, iOS 5 feature full Twitter integration that allow your to tweet directly from other apps like maps, photos, YouTube or Safari. No need to open up the Twitter application.

Photos now work in the iCloud, allowing seamless sharing to all your other iOS devices. Photo editing tools have been upgraded to allow for cropping and rotating as well as auto-enhancing and red-eye removal.

The iCloud, which was opened up this morning prior to the iOS launch, allows for you to back up and restore your device without needing your home computer. You can also activate your device and download free iOS updates to your device without needing that pesky USB cord.

Here’s a video about many of the changes in iOS 5 –

You can currently download iOS 5 via iTunes.