As our own Adrian Kingsley-Hughes covered earlier today, Apple has released iOS 5.0.1 via a 44.6MB over-the-air update to address problems that some users have been experiencing with decreased battery life.
Apple specifically mentions the following fixes:
Fixes bugs affecting battery life
Adds Multitasking Gestures for original iPad
Resolves bugs with Documents in the Cloud
Improves voice recognition for Australian users using dictation
I downloaded it OTA on my iPhone 4/GSM but it never rebooted fully and was stuck on the black screen with the white Apple and progress bar for a while. I waited a few minutes and powered it up again and it rebooted to the springboard without a problem.
I haven't experienced the battery issue on my iPhone 4 with iOS 5, but my loaner iPhone 4S seemed to have less run time than I was used to -- although I never performed full benchmarks.
Unless you've been having issues, my advice is to wait until at least Monday before installing iOS 5.0.1 to see how things shake out. Either way, make sure that you perform a full backup before installing that bad boy.
Update: more screenshots from the installation process on my iPhone 4/GSM:
Have you installed iOS 5.0.1 yet? Are you going to?