The big news last week was the announcement of the third generation iPad, but Apple also updated the operating system for the iPhone and iPad. This is not a major update, but it does add some nice new features and fix a few bugs.
As always, you can update your iPhone or iPad by connecting it to your computer and using iTunes to download and apply the upate. However, if you already had iOS 5 on your device, you can easily update to iOS 5.1 without even connecting to your computer. Just go to Settings -> General -> Software Update. The update only took me around 20 minutes or so, but just to be safe you should plug in your iPhone or iPad so that it does not run out of power throughout the update.
Once you update, here are the major changes that you will see:
Lockscreen Camera. With iOS 5.0, you could double-tap the home button when your iPhone screen was locked to see an icon that you could tap to snap a quick picture. Apple has now made the process even faster. In iOS 5.1, there is always a camera icon at the bottom of your lock screen, Just place your finger on the camera and swipe up to start taking pictures. This is a nice improvement that really speeds up the process of taking a picture and will result in fewer missed opportunities.
Photo Stream. If you use the iCloud Photo Stream feature, you now have the ability to delete pictures from the stream. So if you take three pictures and only one them is any good, delete the bad ones and you won't have to worry about them showing up on your other iCloud devices.
Face Detection. In yet another camera-related improvement, detected faces will now be highlighted in the camera app so you can see that the iPhone is trying to keep faces in focus.
4G Speed ... sorta. If you use AT&T and if you live in a city that has HSPA+, the iPhone 4S can get even faster 3G service than earlier iPhones, which means you can see up to 5.8 Mbps upload and 14.4 Mbps download speeds. When using iOS 5.1 on an iPhone 4S, the iPhone now calls this "4G" at the top left instead of "3G". This is just a change in the label; the iPhone 4S is not any faster. But AT&T insists that it is fair to call this increased speed 4G, and now Apple agrees as well. Lex Friedman of Macworld wrote a good explanation of this change.
Better Audio for Video. Apple says that iOS 5.1 has louder and clearer audio for TV shows and movies. I haven't noticed this yet, but I suppose that sounds good.
Genius Match. If you pay for iTunes Match, you now get Genius matches and playlists.
Location Services Icons. Instead of just having one location services icon at the top of the screen to alert you that your iPhone is keeping track of your current location, there are now three different icons depending upon the status. For example, if the only reason that your iPhone is watching your location is that you instructed the Reminders app to let you know when you arrive at or leave a location (Apple calls this geofencing), you now see an outlined icon.
Security Updates. As with any iOS update, Apple improved the security of the operating system in this update. If you want the details, read this page on the Apple's website.
Free Manual. To give us all the nitty gritty details on iOS 5.1, Apple produced a manual for iOS 5.1 as a free iBook. To download it on your iPhone or iPad, click here: 
