How I safely rollback from iOS 4.1 to iOS 4.0.2 without jailbreaking iPhone 4

There is no safe way to rollback from iOS 4.1 to 4.0.2 - the only way to do so is by hacking your iPhone, which jailbreaking is the pretty word for.
An Apple store will not do this for you.
What sort of battery drain issue and what troubleshooting steps have you tried to determine the cause of the battery drain and to resolve it?
 MacBook Pro 15" Intel Core 2 Duo/2.53GHz/4GB RAM/500GB HD Mac OS X (10.6.4)  iPod w/Video 30GB,  iPhone 4 32GB

HI,
Perhaps not such a good idea.
http://www.pcworld.com/article/199834/how_to_jailbreak_your_ipad_plus_8_things_to_do_with_it.html
Alternatively, check here for optimizing the iPhone battery.
http://www.apple.com/batteries/iphone.html
Carolyn
27" iMac 3.2GHz Intel Core i3 MBAir iPad 32GB iPhone iOS 4.0.1 iPod Nano Mac OS X (10.6.4) QTPro Intuos Tablet Epson Olympus Airport JBL

Im pretty sure you cant. I called the Apple store by me before I attempted to update, and they told me it something that they do not do. The latest and greatest updates are used. I asked even if the latest update it messes up a perfectly good phone and you want to downgrade? They said yes. I was surprised at this for sure.
Dell Studio XPS 8000 Windows 7

Thanks for bringing these issues up folks. Ive been resisting the update until I had time to read what users are saying about it, and bless you all, Im convinced that I need to wait. Im sorry for all who are experiencing trouble, but I really appreciate that youve taken the time to share this valuable feedback with the rest of us.
MacBookPro Mac OS X (10.6.4) iPhone 3GS, iPhone 4

You people know nothing. You dont need to Jailbreak to accomplish this. There isnt even a public Jailbreak for 4.1, just iBSS keys released for iPhone - iPhone 4, v1.0 - 4.1, and iPod touch - iPod touch 4G, v1.0 - 4.1. You need to have your SHSHs (signature hashes) saved for 4.0.2 in order to downgrade to it, and redirect gs.apple.com to either localhost (127.0.0.1) or Cydias servers. Youll need your SHSHs on file to downgrade, otherwise, there is no other way unless the phone is Jailbroken and the boot rom is pwned. If you have not saved the 4.0.2 SHSHs already, then its too late, and you are stuck on 4.1. You should really consider saving them for when you need them at a time like this. This wiki page will tell you newbies everything there is to know about iPhone, iPod touch, iPad, and iOS.
http://theiphonewiki.com/
Late 2008 Unibody Macbook 13inch Mac OS X (10.6.4) Black 32 GB iPhone 4 - iOS 4.0.1