may be my this topic help you a little bit.
Script :: there are lot of sites provide free directory script but i am always go with phpld, there are free and paid both var. available. if you dont like to invest 30$ then register you acc there and you will get phpld var 2.2 free so download it.
Installation :: installation is also easy and script have read me file. just upload all files into your hosting by usin any ftp client or you can use browser upload too aswell becaz this is a small script.
then run your site and script automatically farward you to installation page. follow all steps and your directory is ready.
than understand all function and start making your category. and your complete directory is live.
if you have more question then ask here may be i will help you. i am not too good but can help you in this field. also not good in writing thats why i am not have any content site so sorry if you unable to understand my post