I noticed others having the same issue of the Iphone 4 locking up on them. I wanted to add the additional remark that I had noticed in the week or so previous that Apps were constantly acting tempermental and kicking me off repeatedly. This was true even of System App. I would need to click back on ten times or so just to accomplish the task at hand. I had attempted resets, updates and even tried hardwiring back to itunes. I thought it was an overheating issue and would just leave it alone for a while and come back to it and it was then fine. When it then locked up in the OFF position I panicked thinking it was dead and I was not a happy camper. I then had the idea to perform a hard reset while the phone was on the charger and this worked. The phone continues to work a bit slower then before, in that the keys seem to lag. I believe that there is a provessor issue. I am not sure if this is something that Apple has taken into consideration and lead to the switch on the new units. If so, is this something that will be taken into consideration for customers with older units that are now having issues with this freeze? If Apple is not aware of any issue with the processor, is this something that they might be looking into? If the problem resides in a falty processor, then an exchange will not resolve the issue, only prolonge it. This is unless the new units contain a new processor. Either that, or is there a program in place to trade an Iphone 4 for a 4s if such an issue occurs? Assuming the 4s proccesor is free of such issues. Sorry, there are many questions and issues in this...
To allow your iPhone to function normally, so you can assess any problems. Restore the Firmware with iTunes, at the end when prompted, Restore as New. When finished see if your iPhone functions as you expect. If not, make appointment with Apple Genius and show them the problems you are experiencing, so that a resolution can be made.