Wow. This is unprecedented. What are they going to do? 60 day return period with no restocking fee? Free bumpers for everyone?
I think it'll be an all out pro PR offensive.
They will announce/reveal 4.01 with the "improved signal display", and reiterate that the antenna on the iPhone is actually better (probably true), and that all phones are susceptible to signal loss if held a certain way (true, but massively disingenuous). They'll also talk about how few people have returned them for a refund due to this issue, but they will extend that offer anyway.
There may be some announcement of cheap/free bumpers, but if so it will be presented as something that helps ALL phones avoid interference, not just the iPhone 4, and they're doing it because they want their customers to have the best experience. These bumpers will be either black, or a different "I have the free signal panic bumper" color to keep enticing people to pay $30 for a $3 piece of plastic.
I suspect they hope that this message and the subsequent articles by the carefully picked pro-Apple press will be enough to make the signal issue go away, or at least become something people have no interest in talking about any more.
*Either that, or Jobs is going to come out on stage and give a demonstration of how to hold the phone the right way.
http://www.theregister.co.uk/2009/01/02/apple_glove_patent/
Edit: And it looks like someone's beaten me to the joke:
Where do you live?
Have you had any other network issues -- dropped calls or an inability to dial out -- either with iPhone4 or a previous iPhone model?
Is there no effect on your call or data quality (either as reported by 'bars' or subjectively experienced) when touching 'the gap'?
Having just checked, seems I can drop my bars down from 4 to 3 by putting my thumb across the famous gap.