Hello,
I you need to use same GAnalytics code for all your site versions (desktop, pda, iphone, ...), try to use a system plugin that automaticly add code in your pages.
Elsewhere, you can simply add the GAnalytics code in each of your used templates.
In the GA documentation, they said that low-end mobile devices code (server side) can be used for WAP (and iMode) devices... In my case i will try to use it only for thoses mobiles and use normal Javascript code for modern ones.
Hope it will help