This is how to install NEW iOS 7 without a Dev account or UDID
Step 1 Download the latest official iOS for your device This will be iOS 6.1.4 for iPhone 5 and iOS 6.1.4 for all other supported devices: http://bit.ly/16Vt2lU
(Download Link for iPhone 5 GSM AT&T 6.1.4) http://bit.ly/16Vt2lU
Step 2 Download NEW iOS 7 Beta 4 for your device (Click LINK 3 next to the description of your device for the direct .ipsw) http://bit.ly/16Vt2lU ...
Backup Link for iOS 7 beta 4 Direct .ipsw make sure to highlight the link then right click to open or copy and paste once on the site: http://bit.ly/16Vt2lU
Step 3 make sure your device is connected via USB and open up iTunes on restore hit the shift and left mouse click buttons down together this will allow you to manually search for the iOS you downloaded for iPhone 5 you would select iOS 6.1.4 for all other devices you would select iOS 6.1.3
Step 4 Once the device has restored make sure to setup as new and that you get to the home screen.
Step 5 Now on the Check for updates button hit shift and left mouse click down together this time you need to select iOS 7 for your device now when the device finishes updating it will be on iOS 7 activated.
IMPORTANT the device will work as normal you can Sync from a saved backup install apps, make calls and messages / iMessage etc... also you will be able to OTA all the upcoming beta's.