Owners of the Transformer TF300 will be very excited to learn that Asus confirmed availability of Android 4.1, Jelly Bean via its Facebook page on Saturday.
This update will be over-the-air, which should notify you of the necessary firmware. If not, or you want to try “pushing” it yourself: Menu > Settings > About tablet > System Firmware Update > Check Update.
For the rest of us, it’s good advice to keep checking for an update. Asus plans to reveal plans for other devices in the “near future.”