I'm looking for some information on what the common left handed shooter mistakes are and how to correct them. Any and all help appreciated!!

Common mistakes? Believing that they're at a disadvantage and less capable with right handed guns.

For ARs keep the firing hand grip in place during weapon manipulations, and learn to manipulate right handed controls. 

Aside from what was mentioned above, that's a pretty broad question. There are countless mistakes that are possible, and one's dominant hand has little or nothing to do with most of them. If you ask a more specific question, you'll get a more specific answer.

buying left handed bolt rifles and expecting to have a resale market when you're bored with said rifle. lol

source- lefty here...

Shooting low and right. Trigger control is key for handgun shooting. While right handed shooters pull low and left. Not a big deal. Dry fire helps get used to the trigger and keep the sights steady. 

I like being a lefty. I have a Vickers Glock slide stop lever. It has a small shelf that stands out from slide. On emergency mag changes I insert the mag and just swipe off the slide lever as part of returning to my two handed grip. Being a lefty allows for cheats like that. For ARs: I have a malfunction, I just rotate my eyes and Im looking into the ejection port. No need to flip the gun like a rightie. On handguns my tap, rack and bang clears stove pipes better because of the angle and direction of my hand. Only issue is getting left handed gear.

Please delete.  Accidental repost.

This just reinforces what I have learned from one of the best left handed shooters I have ever worked for...Tom Bullins.  He owns Trigger-Time and he once told me that all gun were secretly made for left handed shooters ;)

Nailed it. I've never had any problems keeping up with righties. I went through a combative pistol course with a 1911, and kept up with all the H&Ks and Glocks--even with reloads. It's all about how much time you are willing to invest in training, and learning how to manipulate what you have.

There are no "lefty" mistakes. In fact, left handed people have a few small advantages with some platforms. Don't buy into the gimmicks.

Pistol reloads can be just as fast.
Shotguns can be emergency loaded faster.
Revolvers can be speed loaded as fast.
Bolt guns can be run very fast from supported positions.

With an AR, a reload with retention might be called for vs a  tac reload.

Anyone know of any information/resources on the 'net that is specific to lefties? I'm thinking basic drills I can do, etc, etc.

I took a class with the guy who has won the most PPC national championships. I thought that he might give me some secret ninja way to shoot. His advice was this simple. "Line up the sights and pull the trigger." Seriously, don't overthink it. There is no "lefty" way to do it.

As a fellow lefty, I'd be happy to share what I have found.

Shooting Southpaw is only a disadvantage if you let yourself believe that. All guns were secretly made for lefties.

Handguns:

get an ambi slide release and mag release. OR rack the slide with a secure overhand grip when finished with reloads or malfunctions and stop worrying about the damn "hollywood button". The only positive use for it is clearing a double feed. You DO practice clearing double feeds don't you?  

For the mag release, if it absolutely can mot be moved from being "right handed", use your trigger finger to hit it.

When practicing one handed, you can rack your slide by catching the ejection port on your holster, belt buckle, etc. Righties do jot have this option.

AR Platforms:

Hold the rifle as you would shoot it. Notice how your thumb comfortably reaches the forward assist? Notice how your trigger finger can hit the bolt catch? Notice how you can actually look into the chamber to see what is wrong when your gun goes *click* instead of *bang*?

Use your trigger finger to sweep the fire select from safe to fire or get an ambi one. Mag changes can be done just as fast as the righties do it if you PRACTICE!!

Shotguns:

So the safety on an 870 is kind of a bitch. Meh. We can still reach and manipulate everything else just the same and our reloads can be done MUCH faster. Why? Because it's easier for us to load the first shell into the chamber and rack the action forward.

I believe everything else I wanted to cover has already been hit on.