My two main references for the snippets of background information are:
Bloody Gallipoli: The New Zealanders' Story, by Richard Stowers. Published by David Bateman, 2005.
Gallipoli: Untold stories from war correspondent Charles Bean and front-line Anzacs. A 90th Anniversary Tribute. By Jonathan King and Michael Bowers. Published by Random House NZ, 2005.
Information about those who died I found at the Commonwealth War Graves Commission: http://www.cwgc.org/find-war-dead.aspx?cpage=1
Sir Ian Hamilton's despatches are available at http://www.1914-1918.net/hamiltons_gallipoli_despatch_3.html
Other Anzac diaries on the Web:
http://www.thekivellfamily.co.nz/military_history/ralphs_diaries/Ralph_Doughty.html (diary of a gunner in the 2nd battery of the NZ Artillery)
If you want to add any other links to Anzac material (especially diaries), or have any comments on any of the Gallipoli Diary webpages, please add them in the comments on this page.