How to update:

Let's get the usual warnings out of the way: don't do this. iOS 9 is beta software, it doesn't work right, it'll void your warranty.

But if you're going to update to the beta anyway, you don't need to pay money to a scummy registration service or beg a developer. You can do it for free, today, without anything more than a copy of iTunes.

Here's how:

- Download the beta for your specific hardware (I'm not linking it, but the usual suspects have it).
- If the beta is zipped or RAR'ed, uncompress it until it is an ipsw file.
- Plug your iOS device into iTunes
- Option-click the "Update" button (Shift-click on Windows). Do NOT use "restore".
- Let your iPhone update. iTunes might crash at some point, but it doesn't matter.

That's it. As long as you use Update instead of Restore, iOS won't ask for any developer info or verify your firmware.