Luckily I have some mildly magical tools around like thermoformable plastic (that just takes hot water). My phone is an HTC Vivid, and I didn’t want to go out and buy anyting.
I then used a 1/4 x 20 threaded insert I had (fits on standard tripods) and wrapped it onto the plastic as I formed it.
I pulled the phone (eventually, keep in mind any odd/non-drafted areas,, like the headphone jack may make it hard to remove,, think about that FIRST!)
Then came back in and used my dremel tool (I destroyed a flex shaft,, arrrgh!) to cut out the holes and openings to use the home buttons, volume, camera, flash, and power buttons.
Voila, when it was all ready (and still rather hideous) I’m able to put my camera on any tripod and fire away! Next up,, making a quickie steadicam so I can shoot action easily,, and maybe finishing/painting my contraption to reduce the hideousness.