This list has 15 iPhone hacks and tricks that will give you that extra functionality so you can truly optimize your iPhone. These modifications should certainly enhance your mobile experience and simply make your life easier.

We have tested all of these iPhone hacks, and they all work.

 1. How to get Push Gmail on your iPhone

While the new iPhone OS 3.0 has push notifications, it failed to include a push version of Gmail. So, while true push Gmail for the iPhone is yet to exist, there is a very, very good work around that uses an iPhone app called Prowl.

Currently, the iPhone uses fetch, as opposed to push, which means that emails aren’t forwarded to your phone until your phone goes lookin’ for them. While the difference isn’t huge, Push gets you your emails in real time. You also save battery, because now your iPhone doesn’t have to use resources to go checking for emails – they’re just automatically forwarded by a server. 

So how do you get push Gmail?

It’s simple. There is an application in the iTunes App Store called Prowl – Growl Client (link opens iTunes) and it allows your iPhone to connect with the famous Growl (follow link to download) program. Growl is a simple program that has one funtion – to notify you. It alerts you of whatever you tell it to. It can alert you when something is finished downloading, when you get an IM, when someone mentions you on twitter, when you get a new email, and more.

So with Prowl, a $3 iPhone application, every notification from Growl gets pushed right to your iPhone. That means when you get a new email, you’ll be notified by Growl on your computer, and by Prowl on your iPhone. Simply download Growl and set it up to notify you of new emails on Gmail. It’s not true push, but it’s pretty damn close…and it accomplishes the same exact thing.

Note: Prowl only works with Growl on Macs as of now. There is a Growl client for Windows, but it doesn’t work with Prowl yet. It will in the next update, so just hang on Windows users. 

2. How to enable tethering now (prior to AT&T allowing it)

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 1. Install iPhone 3.0:

Get On With iPhone 3.0: Download and Install Now

2. Go to http://tr.im/oS1h on your iPhone’s Safari browser

Go here for the rest of the guide. 

This process only takes minutes and does not require jailbreaking. You will be able to tether very easily, via Bluetooth or via USB. It works perfectly.

WARNINGS:

• AT&T could be charging you. Nobody knows.
• Do this at your own risk. 

3. How to sync your iPhone with multiple computers

 Apple only allows you to sync your iPhone with one iTunes library at a time. When you attempt to sync your iPhone to another computer, you get the following message.

There is an easy way to "trick” iTunes. All you need to do is switch the "Library Persistent ID”. 

Read "How to sync your iPhone with multiple computers” for the full step-by-step process. 

4. How to enable Emoji icons on iPhone 3.0

[image via iphonedownloadblog.com]

1. Install Spell Number from the iTunes App Store (it’s free)

2. Launch the app 

3. Type 91929394.59

4. Press the Home button

5. Go to Settings > General > Keyboards

6. Select Emoji under Japanese 

7. Delete the app (if you want) because the emoji icons will still be there

5. How to turn off the iPhone’s accelerometer

Have you ever tried reading something on your iPhone while laying in bed? Well then you’ve certainly gotten annoyed at the accelerometer, which flips the image from portrait to landscape with the slightest turn. Reading on the iPhone while laying down is no easy task, and you’ll be distracted by constantly having to position the phone a specific way to keep it from flipping. That’s why it would be great to have the option to simply turn off the accelerometer for a while.

 Here’s how you do it:

1. Jailbreak your iPhone (follow the link for instructions).

2. Go to Cydia.

3. Search for Boss Prefs.

4. Install it.

5. Go back to Cydia and search for Rotation Inhibitor.

6. Install it.

7. To toggle rotation on and off, simply open up Boss Prefs, and you’ll now see a Rotation option in there.

Note: There is one problem with this app: you can only lock your screen in portrait mode, not landscape. Also, it will crash springboard on iPhone 3GS

our iPhone (Go here for simple instructions.)

2. Go to Cydia

3. Search and download 5-Row QWERTY

Note: work only on iPhone 2.2.1 developer has no update for 3.0 at this time.