strange ftp type question

i have 250mb of webspace with my isp and i upload pics and vids etc to it for ppl to d/l all the time but i can only use the url to gain access to the file. i have seen a very simple type of website (if u can call it that) on somones webspace that allowed you to look at the files on there and click the one you wish to d/l. it was a simple white background with bullet points (kinda like a folder tree) ith the files listed. does anyone have a clue how i could do this?