Apple released iOS 5.0.1 through iTunes and then over-the-air shortly after. This is the first public OTA update Apple has done.
In the past the fact that you had to use a PC to update your wireless devices was a major gripe among iOS users. While Google has always used wireless updates to keep Android up-to-date, Apple preferred to require a connection to a computer to do an update. With that said, Apple devices generally have the updated version of the operating system where a large majority of Android devices are using an older version of the OS.
To update your iOS device wirelessly simply go to Settings > General/Software Update, on this screen you will be presented with any and all available updates.