Microsoft has released a native Outlook Web App client for iPhone and iPad devices. The client is available for download from the iTunes store: OWA for iPhone and OWA for iPad.
Read more at source:http://blogs.technet.com/b/uspartner_ts2team/archive/2013/07/16/outlook-web-app-client-now-available-for-iphone-and-ipad.aspx
Cheers,
Anderson Patricio
http://www.msexchange.org/blogs/patricio/
http://www.andersonpatricio.ca
Twitter: @apatricio