When iOS 4.1 was released in beta form yesterday, we assumed it would be at least a couple of weeks before we saw any sort of update released to the public. We were proven wrong, however, as iOS 4.0.1 is currently rolling out to iPhones. This update includes includes a fix to improve "the formula to determine how many bars of signal strength to display," among other fixes. We'll update the post with any other changes found in the iOS 4.0.1.
This is definitely a surprise move from Apple, especially since iOS 4.1 was put into beta yesterday. Historically it's taken longer for Apple to push out a x.0.1 update, as well, so it definitely seems like they wanted to get their purported signal fix out before their press conference tomorrow. Perhaps now that an update has been pushed out, we'll be seeing the jailbreak and unlock for iOS 4 released, as long as 4.0.1 doesn't plug any holes. Have you downloaded iOS 4.0.1? What are your findings?
UPDATE: It looks like iOS 3.2.1 has been released for iPad as well. This update includes a fix to improve Wi-Fi connectivity and adds Bing as a search option in Safari, among other bug fixes.