iPhone users, stand ready, because it appears that the OS 3.0 upgrade should be arriving between 5pm and 7pm today (UK time).
Following up reports that it was delayed until tomorrow, Twitter user @richardlai checked out different Apple sites around the world and discovered that Apple Singapore was reporting 18 June, while Apple India was reporting 17 June.
A bit of timezone jiggery-pokery gives us the times above, which translates to 4pm to 6pm in the rest of Western Europe, and somewhere between midday and 2pm on the East Coast of the United States.
Make sure your iPhone's plugged in and ready to sync between those times, if you want to be the first to get the update.
Update: Some sites are reporting the update could arrive sooner, with MacFormat claiming 3pm. We'll find out shortly, we suppose!
Update II: 3pm comes and goes with no upgrade. We're putting our money on 6pm GMT, as Hong Kong's iPhone users claim to have received a text saying that it'll be arriving at that time.
Update III: Thanks to commenter Jason for pointing out that the update seems to be available in Australia. See the link below for more details.
Update IV: The Apple iPhone 3.0 software update is now live in the UK, see link below.