This slinky little number is the Sinjimorou Sync Stand, a low-cost stand for iDevices of various shapes and sizes.
It will happily hold your iPhone 4, even if it’s wearing its bumper or some other slim(ish) protective case. It holds various different older iPhone and iPod models too, horizontally or vertically.
Your devices’s standard charging/syncing cable fits snugly into the stand from the back, curling upwards at the front behind the plastic of the stand.
Downside: there’s no grip on the foot, so if the stand is on a shiny desktop, you might find it sliding around when you try and tap on the device.
You can buy one for $18 from Amazon.