The Battle of the White Umfolozi took place between the Voortrekkers and the Zulu's eleven days after the Battle of Blood River.

Almost every source differs in its account of the events of this battle, but the majority of sources say that the Zulu's defeated the British.

The Voortrekker commando under Commandant Karel Landman was led into a trap by a Zulu prisoner, where they were ambushed by the Zulu army. Alexander Harvey Biggar, a British officer and Natal pioneer who had joined the Voortrekker commando to avenge the death of his two sons at the hands of Zulu warriors, was killed along with five others Voortrekkers in the running fight while trying to escape.

Despite their success, the Zulu casualties were many (no sources give exact numbers) and Zulu leader Dingaan was unable to return to his capital. After his brother Mpande joined forces with a trekker commando, the Zulus were defeated at Maqonqo in February 1840. Dingaan fled north where he was killed by the Swazi.

If you would like to read an interesting account of this battle and the Battle of Blood River visit: 2000 Philip Atkinson's a Theory Of Civilization (chapter 9, the Battle of Blood River)

References:

1. Muller, C.F.J. (ed)(1981). Five Hundred years: a history of South Africa; 3rd rev. ed., Pretoria: Academica, p. 167.
2. Kruger, D.W. (ed)(1972). Dictionary of South African Biography, Cape Town: Human Sciences Research Council, v. 1, p. 73.
3. The battle of Blood River from Wikipedia [online], available at: en.wikipedia.org [accessed 18 December 2009]
4. Giliomee et al. (2007), New History of South Africa. Tafelberg Publishers: Cape Town. p. 146.