Is it possible to have a single checkbox NOT selected by default?

For example I am adding a bit of extra code so that when a user ticks this box it also sends an email to the website admin. I dont want this to happen everytime a user updates their details. Only when the checkbox is checked.

Thanks!

[SOLVED] - just realised you just just multiple instead, but only have one value.

Post edited by: saraheagle, at: 2010/10/14 18:53