UPDATE 2: Andrew points out in the comments that this may be the result of devs using Xcode to install Beta 4 rather than iTunes 8.2, which is required. We have no way of testing this, but if you are having trouble, and using Xcode, try switching to iTunes 8.2 and installing that way.
UPDATE: Devs responding to @theiphoneblog via Twitter are reporting that, for them at least, the PSOD is temporary and/or goes away after a reboot. Let us know how it's working for you.
ORIGINAL: Some of the comments in our recent iPhone 3.0 Beta 4 release post, purportedly from registered developers, suggest that at least a few installations are failing with the dreaded "pink screen of death".
The PSOD was seen last year when, during the 2.0 Beta cycle, Apple was tardy with Beta 3 and the previous beta timed out. We're not certain what's going on this time. Developers and their iPhones have to be registered with Apple in order to properly activate. If the procedure Apple is using to verify registration has changed, or is otherwise failing for a percentage of developers, that could be annoying at the least, show-stopper at worst.
If repeated attempts are succeeding for you, or if you've found out anything else that's getting things working, please drop a note in our comments or direct your fellow registered developers to the proper trouble-shooting resources.