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)