The petite tender (aka: teres major) is a small, seldom used shoulder muscle.

Shhh, this is our little secret: Due to lack of use, the petite tender is arguably the second most tender cut after the tenderloin. An excellent cut of beef for a dinner of 2. Can be pan seared, roasted or grilled. 

Teres Major...ly...WRONG! (The verdict is in)
http://colescuts.com/2012/03/04/teres-major-ly-wrong/

Braising tips - Esquire.com
http://www.esquire.com/features/recipes-for-men/ESQ0307braise

2frugalfoodies.com
http://2frugalfoodies.com/recipes/dinner/teres-major-with-a-cabernet-reduction/

The Skirt Steak is cut from the diaphram. As a hard worked muscle group, it can be tough, but is renowned for its flavor. It's often well marbled and distinctly grained.

It's best to marinate the Skirt Steak briefly, then pan sear, broil or grill quickly (medium coals/flame). Make sure to cut across the grain before serving medium rare to rare.

Recipes & Tips:

From the Healthy Green Kitchen website -
Grass Fed Skirt Steak with Cilantro and Preserved Lemon Gremolata

Epicurious.com
Grilled Spice-Rubbed Skirt Steak

The Flat Iron is a top blade, or shoulder cut. Arguably the second most tender cut (considered by some a tough cut that needs marinating) if prepared correctly. Despite the 'Old World' sounding name, the Flat Iron is actually a new cut (developed in 2002). A must try for the adventurous amateur chef.

A quick light marinade is preferred. grill or pan sear quickly over medium-high heat. As with most grass-fed beef, serve medium-rare to rare and cut across the grain.

http://confessionsofabutcher.blogspot.com/2005/12/flat-iron-steak-hype-or-heart.html

Recipes & Tips:

Epicurious.com
Grilled Flat Iron Steak with Chimichurri Sauce (warning: lots of garlic!)

Often with an obvious grain. Can be tough, so a marinade is suggested. Grill or broil on medium-high heat and serve medium rare.

Recipes & Tips:

TheCityCook.com
Cooking Skirt and Hanger Steaks (excellent pan/broiler advice)

FoodAndWine.com
Herbed Hanger Steak

Our "London Broils" are large cuts of meat from the lean top round. Often over three pounds.

Best slow cooked on the grill, and accepts marinading well (preferred, overnight). Great for casual group cookouts where you're not looking to impress, but satisfy.

Recipes & Tips

RIFarmsAndFood.com
Grass-fed London Broil - Excellent grilling/tenderizing advice.

FoodWishes.blogspot.com
Cooking Grass-fed Beef: Episode 1 - Top Round "London Broil" (video)

A flank steak is cut from the abdominal muscle of the cow. It is a tough, but flavorful cut of meat best marinated then quick seared, broiled or grilled.

It's the flavor that makes this cut stand out, but it is essential to remember to cut it thinly and across the grain on a diagonal.

Recipes & Tips:

OChef.com
Are Flank Steak and Skirt Steak Identical Cuts? - Professional answer to a common question.

SimplyRecipes.com
Grilled Marinated Flank Steak

Epicurious.com
Grilled Asian Flank Steak...