I'm a huge fan of Howard, Jimmy, and Adam Carolla, and I watch/listen to them on whatever they're on as much as I can (The Howard Stern Show on Sirius, Jimmy Kimmel Live, Loveline and now The Adam Carolla Show). On multiple occasions it's been revealed Jimmy has atleast a fairly big one, just as Howard and Adam have complained about their little ones.
Just a few weeks ago I was listening to the Adam Carolla Show when it came up again. I forget the exact conversation, but when Adam did make an off the cuff remark about Kimmels hog, his co-host Teresa inquired more, clearly excited about that revelation. Adam said not only was it big but that it was a "good walking around in the gym size", meaning that Jimmy's a "shower".
Sarah Silverman has also, I remember, called Jimmy's cock "perfect", again, sort of off the cuff, when (I think) she was discussing his surgury he had to get for his urethra that was closing up.
So those are the facts from a fan, never thought I'd write a couple paragraphs related to JimKims schlong.