if you dont' want to be stuck in queues in the 1st few weeks at the coop shop, just check pweb as sometimes they mention it there on the tute rego page, otherwise, look in your unit outlines
I don't know which campus you are on but the coop at Bankstown had their lists up today, you can also check the text lists on the coop site or as Lara said your unit outline will tell u the texts, required and/or reccommended
have u check the co-opbookshop website http://www.coop-bookshop.com.au/bookshop and just follow the interface select uni & campus >select unit number & name it should show u texts required best to get them before university starts otherwise the lines would be long.