I used phpld for a short time and found it to be a great directory script. I am stiil keeping my license for future use just because it will be useful sometime. I wrote a mod or two for phpld, so let me know what you might need in the way of mods.
Try cplinks for a free script, it looks simple and it's free to test. Try the dynalinks version:
cpDynaLinks - a free commercial grade links directory script
I might try it out as well.
OMC