I heard a lot of people talk about Ushahidi, in official site said that The Ushahidi Platform is an open source web application for information collection, vizualisation and interactive mapping, it allows people to collect and share their own stories using various mediums such as SMS, Web Forms, Email or Twitter. so I try to install it on my Dreamhost hosting server. it is have iOS application, it is universal application means work well with iPhone/iPod/iPad once download.
go to http://download.ushahidi.com/ then download Ushahidi, unzip, open readme.html file, check out Required Extensions, Dreamhost offer all of bellowing php extensions: