Bad luck, non-US countries. iBooks won't be available from launch in any country other than the US. That could mean Apple's still to finesse the licensing details with book publishers in each country, or you're just plain out of luck.
While I doubt they could write off one of the most attractive features of the iPad that easily, it's disappointing that there'll be a delay in other countries. Apple's Australian website is one of the first sites to have any trace of the iPad, which confirms the lack of ebooks.
I'll be busy pressing F5 every 10 minutes on the UK Apple site, looking for any sign of the iPad, as I just can't believe Apple could launch the device without ebooks from the get-go in the UK, considering Penguin's a British publisher, Hachette a French one, Macmillan originally Scottish but now German, and Harper Collins a British/American company.