Simple to print and simple to use. If you need something to mount your iphone 4 to the velbon tripod, consider making one of these. I found it works very nicely, holds well, and the phone quickly snaps in and out.
If you want to modify it, I have included the SolidWorks design files.
I printed this on a Replicator 2 but it should be printable on others. It is likely that a wide range of print settings will work. I printed it on Makerware medium settings.