thats easy:
Just go to your profile page and hit "forum profile information" on the side
type your siggy phrase into the signature box and hit 'update profile'
if you'd like to add a picture put this:
[img][/img]
between the two put the direct link to the photo u wish to use, or one from your photo sharing account. personally i use iaza to upload and just edit screenies with gimp cuz u dun need a profile fer iaza.
As for the profile picture...
in the avatar box upload the photo from your computer with the "browse" button
VOILA!
you have your answer!