Yes, it was an OS update that included the iTunes 10.3 Update.
iOS 4.3.3 Software Update
About iOS 4.3.3 Software Update
This update contains changes to the iOS crowd-sourced location database cache including:
Reduces the size of the cache
No longer backs the cache up to iTunes
Deletes the cache entirely when Location Services is turned off
Products compatible with this software update:
• iPhone 4 (GSM model)
• iPhone 3GS
• iPad 2
• iPad
• iPod touch (4th generation)
• iPod touch (3rd generation)
This update is available via iTunes.
Whatever they did, it seems to be affecting many people. Main problem seems to be WiFi connectivity which I haven't checked, but battery not charging, random reboot, battery draining too fast, syncing, etc...
If Apple comes out with 4.3.4 quick, then you know there were problems with 4.3.3.