Similar deal to http://www.ozbargain.com.au/node/122103 except a new code and expiry date.
It's really 30% off when combined with the 10% off 'citizenship' thing they have: http://www.bookworld.com.au/citizenship
I admit you can probably get some books cheaper elsewhere (always check Booko first), but for example I was looking for the new version of Robin Barker's Baby Love book, and with the voucher Bookworld come out $7 cheaper than Angus & Robertson (which was the second cheapest). RRP is $36, so for $21 delivered it's a bargain!
Terms and Conditions: 20% off promotional voucher code is only redeemable on book, CD & DVD purchases and excludes eBooks, eReaders, stationery, calendars, gifts, accessories and Bookworld Gift Card currency.
Promotion is only valid on Australian RRP titles; offer valid until midnight (AEST) Sunday 17 November 2013. To apply this discount to the books and CDs in your basket enter valid voucher code at the checkout then follow the prompts to complete your transaction. Offer only valid to new Bookworld Citizens at www.bookworld.com.au. Visit website for full Bookworld Citizenship terms and conditions. Bookworld reserves the right to cancel or alter the promotion should it be deemed necessary.
Great deal - 30% off with citizenship and this voucher.