As Steve Bell wrote (ref: Microsoft SharePoint on the iPhone) in SharePoint Magazine, SharePoint sites can be browsed in full fidelity on an iPhone. You just need to be in landscape mode in the web browser.
" ... I would not have understood how compelling using SharePoint from a pocket-sized mobile device is, but actually using SharePoint on an iPhone is a bit of a “wow!” experience. SharePoint could open up a whole new universe for iPhone users: the Microsoft universe, which is a very large one...."
So, no need to "mobile enable" SharePoint sites for iPhone users.
For users hooked on to the native iPhone interface, there are options available. I am aware of following 2 products:
Spyk Software Pty Ltd has released a product - iShare which lets you connect to SharePoint sites and content from iPhone. iShare connects to SharePoint using SharePoint's Web Services and so supports WSS 3.0, MOSS 2007 and even SharePoint Online. All content is read-only and security trimmed as per user's access level. Check the product website for screenshots and feature list. The application can be downloaded from iPhone App store.
iSharephone from Webstate connects iPhone to the iSharePhone Server through SSL. The iSharePhone Server authorizes and manages iSharePhone users. The Server in turn connects to the SharePoint server and is either placed in the DMZ or behind the firewall. iSharePhone and SharePoint Portal Server use SSL communication for data encryption. All the data on the iPhone is stored in an encrypted SQLite database. This product is currently in beta stage.
If someone has tried out any of the above applications let me know how the user experience is.
update: Just noticed Joel Oleson's blog post Confessions of a SharePoint iPhone user in which he lists 10 reasons why it’s ok to show your iPhone in a SharePoint Crowd. Interesting post from a self-confessed Microsoft junkie :-)
Check out Filamente!
Filamente, a native iPad & iPhone client for SharePoint, allows you to perform various tasks that you cannot do using a regular web browser on your iPad & iPhone such as document and picture upload, offline access and managing multiple SharePoint sites, let alone editing SharePoint list items.
Full version: http://tinyurl.com/Filamente
Lite version: tinyurl.com/FilamenteLite
Web site: http://www.aircreek.com