Update: In order to jailbreak your device on iOS 5 Beta 6 go HERE.
Apple released iOS 5 Beta 6 earlier today for iPhone, iPod Touch and iPad. You can install iOS 5 Beta 6 on your iPhone, iPod Touch or iPad by a couple of methods listed after the break in a few minutes.
1. With Over The Air (OTA) Update:
In order to install iOS 5 Beta 6 over the air you need to restore your device with with official iOS 5 Beta 5 by following the guide HERE if you have jailbroken your device on beta 5. If your device is not jailbroken then you can proceed with this guide right away.
Step 1: Back up the contents of your device.
Step 2: Go to Settings => General
Step 3: Tap on reset and select 'Erase All Content and Settings'
Step 4: The device will prompt you to confirm your reset a couple of times. Tap on Erase iPhone/iPad/iPod touch.
Step 5: Set up your device once again and reboot.
Step 6: Go to Settings => General.
Step 7: Scroll down to Software Update and tap it. You will see an update notification to iOS 5 Beta 6. Tap Download and Install.
Wait for the download to finish. It is an approximately 144MB update and will take 10-15 minutes depending upon your internet connection.
2. Without OTA Method:
In order to update the software of your iPhone/iPod Touch/iPad without OTA update method for some reason follow this simple guide below.
Step 2: Plugin your device into your Mac or Windows PC and open iTunes.
Step 3: Backup the contents of your iDevice via iTunes.
Step 4: Now go to the device page where you see the device details and a 'Restore' icon under it. Windows users will press Shift and click on restore while Mac users will press Alt and click restore.
Step 5: Locate the IPSW file downloaded for your device in Step 1 and click ok.
That's it. iTunes will take about 10 minutes to update your software. Donot unplug or turn off your PC during the process. Once iTunes is done your device will reboot.
Note: If you are using a software unlocked or jailbroken device then stay away from the update. If you have a factory unlocked device then you may proceed without any worries.