You probably need to grab a few books (like, NOW) about dog training. There are websites you can go to for quick overviews and such, but you really need to read a few different books on the subject. The bottom line is that YOU need to be educated on how to train your dog. It doesn't matter a bit if you had a million dollars to spend on trainers to work with your dog.... if YOU can't be the "alpha" (pack leader) then it won't make any difference. And for YOU to be BE the alpha, you have to understand what it means.
Please don't take this this wrong way, it is not my intention to sound harsh at all. But if you want your dog trained properly it isn't a one time thing that you take him to go do. It is DAILY. What you and he learn must be constantly reinforced every day. Dog training begins the moment they come into your home. It isn't just a class you take with them... it is a lifestyle. Truly. It is which of you goes through the doorway first. It is how you play and praise him. It is how you respond when he jumps on you or comes up and nudges you. It is the process of feeding him. It is where he sleeps even. There is SOOO much to learn and you are going to have to invest a little time in reading to understand how to integrate your pup into your "pack" (your family). Otherwise, you will end up with a big dog that is a terror to live with (not necessarily scary, but UNRULY and rude to guests, destructive, etc).
IT is SOOO worth every minute you spend educating yourself and implementing rules and expectations for your pup.
I won't say not to go to Petsmart (or any other group training class), but there are some very different methods of training out there, and you need to educate yourself on which method you want to use (and put into practice at home throughout his life). As far as I am concerned, the most important part of group training classes is the socialization aspect. All the rest of it, the actual WORK and TRAINING is done at home in between classes.
Here is a link that has dozens of articles on different aspects of understanding your dog. There are tons and tons of opinions, so do some reading so you can make an educated decision about how to train your dog best. You will be amazed at the level you can understand your dog's behaviors (and how to shape them) with just a little reading.
By the way... sounds like a BEAUTIFUL dog!
http://www.dogbreedinfo.com/articles/linksbehavior.htm