You could change the regional setting of the site by browsing to Site Actions > Site Settings > Regional Settings
You could also change the Locale using the following code:
using (SPSite site = new SPSite("http://SITE"))
{
using (SPWeb web = site.OpenWeb())
{
SPRegionalSettings newRegionalSettings = new SPRegionalSettings(web);
// Change to Australia
newRegionalSettings.LocaleId = 3081;
web.RegionalSettings = newRegionalSettings;
web.Update();
}
}
