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The way i do it makes no difference in procedures from making a regular theme and before people will jump and say is not true...
If your target is iPhone/iPod touch is best to make sure you're using the latest stuff when it comes to html and css which will mean html 5 which can be tricky sometime but if you take your time there shouldn't be any problem.
Also is best to take full advantage of what the iPhone can do when it comes to webapps so a different more edge design and features should be achieved in this theme and keep in mind that you must not use flash as it won't show up..unless things will change after January the 27.
As far as coding the XOOPS stuff goes, is exactly the same, using same smarty constants you'd use in a regular theme.
Start from as simple framework as you can and keep in mind that whereas the width of a static theme is usually around 900-1000px when viewed on the computer, the iPhone revolves around 400px so CS or whatever production app you use for design, must be created with that width in mind.
If you code on a mac is best to use the dashcode app which comes with the OS, if on windows you got me there as i don't know what to suggest
With that being said, am in the middle of making a XOOPS admin dedicated for iPhone, also a version of my themes site will also soon be launched on that mobile device.
If by "mobile site" u didn't meant iPhone/iPod touch browsing then most of the above will be useless tips for you
