function loadMimeTypes() {
		$mimeconf = fopen("mimetypes.conf", "r");
		while ($line = fgets($mimeconf, 4096)) {
			$types = explode(" = ", $line);
			foreach ($types as $type) {
				$exts = explode(" ", $type[0]);
				foreach ($exts as $ext) {
					$this->mimeTypes[$ext] = $type[1];
				}
			}
			print_r($this->mimeTypes);
		}
	}

Output from function (printed for each line in the file):

Array
(
    [h] => t
    [a] => s
    [c] => s
    [d] => v
    [b] => m
    [o] => d
    [p] => p
    [s] => g
    [x] => m
    [w] => m
    [v] => i
    [g] => i
    [j] => p
    [l] => a
    [n] => c
    [t] => e
    [m] => p
    [u] => s
    [z] => i
    [r] => t
    [i] => g
    [e] => t
    [q] => t
)

Contents of mimetypes.conf:

hqx = application/mac-binhex40
cpt = application/mac-compactpro
doc = application/msword
bin dms lha lzh exe class so dll = application/octet-stream
oda = application/oda
pdf = application/pdf
ai eps ps = application/postscript
smi smil = application/smil
xls = application/ms-excel
... etc ...