To go along with my other shadow repositories tuned for older versions of MacPorts, I've initiated a "LionPorts" version.
Although the _vast_ majority of ports build and work correctly on systems all the way back to Tiger, it is not always possible or practical to keep all ports retroactive to the oldest systems in the active MacPorts repository.
These repositories contain pegged versions of ports at the last version that worked on various systems, and in some cases modified versions of ports that work on these older systems but with fixes that haven't (as yet) been accepted into the current MacPorts repository for one reason or another. You are free to use them, and contribute to them, as you wish. No guarantees, of course, but these have all been tested out to work for me on these systems.