A brand new pic of Joker and Rachel Dawes from the movie itself, as well as a link to a high definition teaser can be found here:

http://www.aintitcool.com/node/33478

A copy of the new logo only teaser, only in non-HD Youtube quality, that's attached to select copies of The Simpsons Movie can be found here:

http://www.youtube.com/watch?v=boIhrBtsj-Y

It consists of the logo and some dialogue between Bruce and Alfred, as well as our first exposure to Ledger's voice and laugh. You can find an additional piece of Joker speak at the link below. Click or place your cursor over the dollar bill He almost sounds like the Animated Series version of Two-Face here:

http://www.whysoserious.com/d_rt89rrb.htm