Originally iViewer was created for home automation control, but it is a very flexible app, so I thought why not create an EG plugin for it.
The main difference from any of the other iPhone solutions for EG is that iViewer allows you to fully customize the interface that shows up on the iPhone, using our CommandFusion guiDesigner software.
Grab a copy of guiDesigner (requires Windows and .NET 2.0) from our website for free (just need to create an account, no spam we promise!)
The iPhone app is available here:
CF iViewer in the App Store (opens in iTunes)
The plugin is available from our GoogleCode repo:
CommandFusion Plugin.zip = the plugin, just unzip to EG plugins folder.
example.gui.zip = an example guiDesigner project (zipped)
CommandFusionExample.xml = an example EventGhost config (setup to control Media Center, untested, but serves mainly as a starting point on how to use the plugin).
Basic Intro on how to use guiDesigner:
All GUI objects (buttons/sliders/gauges/text/etc) have the ability to be assigned one of three join types:
1. Digital Joins = 0 or 1, on or off, boolean values (used mainly by buttons to show active/inactive states)
2. Analog Joins = 0 - 65535 integer value. Used mainly by sliders/gauges. The value defines the state of the slider/gauge.
3. Serial Joins = any text value. Used mainly by text objects. Allows you to show any text value in the GUI.
So you create a button, give it a join, then when that button is pressed, it generates an event in EG that you can then use to perform your macros.
You can also change the GUI state by sending actions back to the iPhone via the plugin.
You can also create custom commands via the System Manager to send to ANY ethernet device, such as a GlobalCache unit for controlling your AV gear.
Heres how the example guiDesigner project looks:

To make the connection happen, you need to define the port number that the plugin will listen on in the plugin config screen:

Then you change the "Project Properties" in guiDesigner to point to the IP address of your machine running EventGhost, and the port number you chose.
Then to upload the GUI to your iPhone:
1. Start the 'Upload Service' in guiDesigner (via the File menu) after opening your guiDesigner project and saving any changes.
2. Go to the settings of iViewer on your iPhone (via the main iPhone settings app), and enter the GUI File URL as shown in the Upload Service window of guiDesigner.
3. Make sure you enable 'Reload GUI File'.
4. Launch iViewer - it will grab the GUI file from the guiDesigner Upload Service and cache it, then connect to your EventGhost setup, and you're ready to go.
5. Once you are happy with the GUI, go back to the iViewer settings and turn off 'Reload GUI File'. Now iViewer will use the cached GUI file on each load and you no longer need guiDesigner running.
The cost: FREE
guiDesigner is FREE, and iViewer is FREE, and the plugin is FREE, so you can set this all up without costing you a cent. The only limitation of this is that you are restricted to a single portrait and single landscape page. Page flips and subpages are a feature that must be unlocked by purchasing a license at our website. The app is VERY powerful in the home automation market, so licenses aren't cheap, but we are looking at releasing a version of the app at a much lower price point than our current licensing scheme, which is simplified for use with software such as EventGhost.
I will try and answer all questions via this thread, but we also have a great Google Group for support here:
http://groups.google.com/group/commandfusion