1999 E-150 possible engine oil leak
 

I was changing the engine oil and I noticed something that looks like oil leaking.
I added some pictures here so you guys can tell what it is.
(it's the one with the question mark)
http://i405.photobucket.com/albums/p.../011edited.jpg


http://i405.photobucket.com/albums/p...02edited-1.jpg

http://i405.photobucket.com/albums/p...bludog/007.jpg

there are oil residue and it feels like a rubber and felt very loose.
is there anything I can do to fix the leaking issue?