I've had that problem with my dog... Luckily its getting better now! I tried all kinds of things to get his attention, but as the other dog got closer he'd get blocked and not pay the slightest bit of attention to me! Even a piece of hotdog dangled in front of his nose didn't work, and he is normally very food crazy. Then I just got really angry. And it worked wonders! If he started acting stupid I'd start telling him what an awful, disobedient boy he was being in a deep, serious voice. I normally don't get angry at him, and if I do its more of an indignant how-could-you-steal-my-chips shrill angry. So he was suprised! And looked startled at me, and got LOTS of praise and treats etc. I did that for a few walks and then he got so he was reachable in his excitment. He is no way near reliable with other dogs, but he's getting there!

Another thing that could help might be to take him to places where there are other dogs, and just sit and be boring. Let him figure out that being a brat isn't going to make him be able to play! Obedience classes are also great, because you can meet other dogs in an organized fashion where people understand your "problem" with him.