how do i uninstall ios 8.0.1?

Only way I can think of is to format the phone back to factory default which would mean it will go back to whatever apple has listed as the current IOS for your phone model. Atm 8.0.1 has been taken down so it should go back to 8.0.0 that's the only thing I can think of. Sorry

i am in the process of doing exactly that and it takes forever. Yes it does eventually take the iPhone back to iOS 8.0

If you do a Factory Reset on iTunes ...Go to the iTunes Preferences and make sure that Automatically Sync is turned OFF

What is "8.0.1" as both iTunes and my iPhone 6 say that 8.0 is the latest update? Is it a beta update?

If your iPhone is on iOS 8 just be thrilled and see if you have phone service. Apple pulled the 8.0.1 Release so there is no way to download it. For all those that didn't do that update be very happy.

You have to plug your device on a mac or pc, launch itunes, download the ipsw corresponding to your device for IOS 8. Next you have to enter into restore mode. Before that, make a backup of youre device on your pc.

After installing IOS 8, you have to restore your backup from your pc or icloud.