It's been a while since the last beta, but per a screenshot sent in by a tipster, Apple's already begun pushing iOS 5.1 beta 3 to development iOS devices. The 77.4MB update curiously isn't live on Apple's developer website just yet (see update), but when it lands we'll hopefully gleam more than "bug fixes and improvements."

Update: Per MacRumors, the build in question is 9B5141a and restores the 3G toggle absent on the iPhone 4S.

Update 2: It's live on the developer portal.

[Thanks, Justin]