Well it's not the full 4.1 we were expecting... but here's a little tidbit from Apple. One of the main features? The update "improves the formula to determine how many bars of signal strength to display." Interesting. We're updating some devices right now, and will report back with what we find. [Thanks to everyone who sent this in]
Update: It looks like iOS 3.2.1 for iPad is coming down the tube, as well. We'll let you know what changes we're seeing!
Update 2: Here's a quick before-and-after shot of the signal meter. Clearly, Apple wasn't yanking any chains about changing the sizes of those leftmost bars.