Today, Apple released iTunes 7.4.2. Apple kindly fixed that small problem where people inadvertently installed custom ringtones on their systems. Thank you, Apple.
Apple also looks out for iPod Touch users. Its new firmware transfer scheme protects users from themselves. You won't accidentally install custom software on the iTouch or access the underlying OS, at least for some time to come. Unfortunately, Apple forgot to protect the public Media partition from read/write access so tools such as Ecamm's iPhoneDrive still work with both the iPhone and iTouch. For now.
Will the iPhone remain so dangerously open? Probably not for long. I give it until the next firmware update. I'll be delighted to be proved wrong.
So where does that leave you? Do you want to tread those dangerous waters and not be protected from yourself? Right now, the realm of social networking seems strongest: Call and write Apple and let them know what you think. Ask them for a public SDK. Ask them to open the iTouch and keep the iPhone open. Otherwise? Welcome to the padded walls and your shiny white straightjacket.
Update: Just to clarify: SendSong still works. All my custom ringtones are gone from iTunes. Renaming to m4r and using Cleverboy's metadata hack did not work. iToner should still work as well as any other solution that writes directly to the iPhone without going through iTunes.
Update 2: I totally forgot about the new authentication chips for video. Thanks everyone who reminded me.