I have done alot of searching on the internet the past few days regarding people reporting problems after upgrading to the 3.1 software, specifically frequent shutdowns of their iphones. On the Apple Support website there are thousands of reports from iphone users far and wide. I contacted apple support yesterday through calling At&t and they agreed to replace the entire handset at no charge even though the warranty has expired long ago, sweet deal ha. I ask the rep why the handset would be replaced if it is an obvious software issue because this did not start until the software hit my phone, my phone completely shuts down about 10 times per day and is useless, she replies that obviously the phone will be preloaded with the new software and goes through extensive testing before it is sent to the user. Can't complain ha. Give them a call if you are having this issue also