My mini schnauzer is a total asshole with other dogs. I've tried taking him out around the neighborhood without a leash but as soon as some stray dog shows up he goes nuts and chases it or start fighting. He won't listen to any commands he usually listens to.
Right now my best solution is to keep him permanently on a leash but I'd like to let him move around more and run free for a few minutes each day without having to worry that he'll hurt himself being an asshole.
If anyone has any tips to correct this aggression thing or could point me to some good tutorials over the internet that would be awesome.

Making animals obey is not complicated - give him a snack when he behaves, hit him in the head when he doesn't .

I don't have any experience with raising dogs but I was always fascinated by Victoria Stilwell's series It's Me or the Dog. A lot of useful tips and visible progress. I recall that she dealt with dog's aggression towards other dogs several times. I can't name a specific episode, though.

thanks I'll check it out

You're welcome & good luck. Don't forget to share how well it goes :).

You must show him who's the boss. So take it to your wife and say "See? This one right here.".

You could try taking him to a dogpark to socialize with other dogs.

Have him socialize first with dogs while you holding the leash.

Also, the most important command a dog should always learn first is a stern NO. You know you are in command of your dog if whenever you give a stern NO command, it ceases what it is doing and fixates on you. Otherwise, you don't have control of your dog.

That, but don't hit with your hand, use a newspaper or something. You don't want your hand associated with a punishment tool or he will bite you eventually.

I'm really not a pro on that subject, I just bring my two cents on what I heard.

Some dogs are just like that, I trained dogs as a profession for a while, I only ever came across 1 dog that given enough exposure to other dogs still didnt do as it was told, there are many methods for teaching dogs to be social, from the basic just walking them in a busy park where other dogs frequent to the more extreme (i have not done this myself but have read about it being used in other countries) putting the dog into a puppy cage and putting the cage with the dog inside into a busy dog walking area and just sitting there and waiting for it to stop going mental at every dog that goes past.

Note: I do not mean abandoning the dog in a cage, you have to still be there to supervise and treat when the dog behaves,

The smaller the dog the bigger the asshole. Look at it this way, it means the dog is healthy and happy. Abused and neglected dogs don't give attitude. That being said I seriously encourage people to adopt abused dogs, they need love too and as soon as you turn it from a scared quivering mess into a total asshole you have successfully rescued him/her.

Similar situation. We have a dachshund mix which is, by law, one of the more stubborn creatures on the planet. Even she behaves relatively well in very controlled environments (doing things many dachshund owners claim 'can't be done'). But when it comes to other animals in the vicinity, all bets are off. The eyes roll back, the ears close and demon critter reveals itself. We have given up.

We have another dog that we have somewhat successfully trained and when she is alone, she can go near other animals... unless the dachshund is around... then they BOTH behave very, very poorly.

All that said, internet advice, books, training vids, etc... those are nice, but I do believe dogs have unique personalities and what works for one may not work for another.

I have a 13 year old short hair miniature dachsi growling at me as I type this, I shit you not. :P

Well my dog is usually really nice and friendly, he doesn't even know how to bark properly. Outside he has been friendly to some stranger dogs if the other dog is friendly too. He just responds really badly to other dogs sometimes. It may be that I've kept him on a leash for a long time and he never really managed to learn proper dog "manners". He listens to "No" commands at home, even to "drop it" commands but outside he gets totally distracted and ignores everything.

As a stop gap for walks, at least until you can get to the root of the attitude / control problem, may I suggest a "gentle leader"? It's not a muzzle but instead helps you control the head. Here's the one we use: http://www.halti.co.uk/

Ours are like that, too. Apart, they're good around other dogs, on walks, etc. Together, they're both a pain in the ass when meeting other dogs.

But I'm certain it goes back to us - the 'parents', if you will - doing something wrong at those times. I say this because the folks at the dog day care where we send them for socialization (and baths, phew!) can get those two to stop their crap with just a word or two. Some people have the knack...