With iOS 4 the iPhone has become a tad better to use. While there are many improvements and totally new features, the following stands out for now.
1. Screen Orientation Lock
So many times I have tilted my iPhone only to find that it wanted a certain orientation while I wanted the other. But now, you are able to lock the screen, albeit in vertical orientation. Double tap the home button and on the Multi task bar, all the way to the left, you will find the orientation lock icon
2. SMS Searching, MMS Disabling and of course, MMS character count.
The iPhones SMS app also got a few new improvements. Most notable are, the ability to toggle off MMS and grouping of messages with multiple recipients. You can also find the character count helpful. The SMS search is the best new feature in this department. It's similar to search in the iOS. SMS search simply live-updates results as you keep adding to your query.
3. New iPod multitasking controls
Double-tapping the home button will bring up the multi-tasking drawer. It provides an easy means to switch from one app to the other. By swiping over to the very left of the drawer, you'll be able to access some minimal iPod controls next to the orientation lock, that you used to get when you tapped home button twice, earlier. Play/pause, forward, back. It's just enough to make some quick adjustments to song selection, but if you want more control, you will need to access the iPod app.
4. Camera Zoom
Yes, I always wanted to zoom the camera on the iPhone, now you can, even though it is digital zoon, which I never use on real pocket cameras, it is better than not, for those close up occasions.
It is good that you can search web and now Wikipedia, from the global search screen
6. The spell check
If you have read this blog, you already know that the languages are not my strongest point and I make spelling errors even while I dream, so thank you for the spell checker.
7. App Specific Location Service
Now you can select by app, if you want to allow it to find your location. You will also see who used location services by a little compass symbol attached to the icon.
8. App folders and Folder on Dock.
I am happy to have a ability to lump apps by folders and sometimes you will see an exclamation mark next to a folder. It is because, one of the apps got an alert! The fact you can drag folders into the dock, is pretty good too.
There are many more but these stuck as important for the moment. You will find more on Gizmodo.