I've never seen this type of spider before and managed to get these two decent (I hope) closeups of it. Andrew from MNS mentioned this as a type of Spiney Spider.
1 Aug 2007: Spider identified! Thanks to Milo for pointing out the web-reference sites.
Specie of Orb Web Spider of family Araneidae
This is a Curved Spiny Spider (Gasteracantha arcuata) a.k.a. Horned Spider

