select with parentID field into multidimensional array?

Hi I have a table which is set out like this ID name parentID I "select * from table" into $result. I then wish to walk through the result such that it creates a multidimensional array sorted with children under parents. Here is a basic eg. ID name parentID 1 books 0 2 movies 0 3 songs 0 4 horror 1 5 love 1 6 horror 2 7 love 2 8 scifi 2 9 IT 4 etc I am trying to write a function that would then insert these into a multidimensional array as such... $array[1] = "books"; $arary[1][4] = "horror"; $array[1][4][9] = "IT"; etc, so I could pull them out into a select dropdown list nicely sorted. I am not sure how to write an array function with an unlimited number of levels. If someone could help out it would be greatly appreciated. Thanks Stephen