In their early stage, before they went apeshit, they actually did do good deeds. I've already seen the Pen & Teller episode as well, and as amusing as I find the two of them, I wouldn't use them as a source of knowledge since they have a tendency of ridiculing everything. But that's my personal opinion.
PETA these days is full of crap, yes. This thread alone shows that, and that's not even the tip of the iceberg, as I'm sure most of us already know.
I don't support any organisation. I do my good deeds without one.