Mark,
As far as comic books go- War comics as a genre didn't really develop until the Korean War in 1950. During WWII there were many references to the war in comic books, in just about every genre, as superheroes and larger than life characters (such as Airboy in Air Fighters and the Blackhawks in Military Comics) fought saboteurs, spies and the axis powers and the more down to earth characters raised victory gardens, dealt with rationing, collected paper and metal for the war effort, and encouraged people to buy war bonds and stamps.
However there were very few comic books that dealt exclusively with the average soldiers/sailors fighting the war. Dell did have War Comics, War Stories and War Heroes and there were probably a few other short series as well as one shots and various backup features that featured war genre stories but what we think of as "war comics" just didn't really take off at this time.
After the Korean war started in 1950 things changed. Superhero comics had been in decline for years and crime comics had been under attack from various quarters so a war comic with a patriotic theme attached to it seemed like a safe bet to show off plenty of action and violence without getting much in the way of complaints.
Ziff-Davis was one of the first to tackle the genre with their very successful G. I. Joe and others soon followed. Within the next few years quite a few publishers jumped on the bandwagon and by the end of 1952 there were numerous war comics on the newsstands. Some took a humorous slant, some featured the larger than life characters (that had been around even during WWII) but many were just about the average fighting man. The genre imploded in 1953 as the Korean war fizzled to a stalemate and many war titles were cancelled that year.
Not all war titles were cancelled though and some publishers kept their foot in the genre and even built their stable of war titles back up again although stories about the glories of WWII came to dominate the genre as the years progressed. By the 1980s most war comics were gone for good with only occasional short-lived revivals.
When Vietnam came along few comics touched on the conflict at the time. Dell's Jungle War Stories and Warren's Blazing Combat were among the few comics to feature Vietnam war stories while the conflict was ongoing in the 1960s. Most publishers didn't do comics on the conflict until years after it was over.
The above synopsis of mine is a very condensed and generalized look at the genre history and there are some publishers whom I'm still woefully ignorant of (I've only looked over the Korean War era Fiction House titles for example). I'm sure others can add to (and correct where needed) what little I've said here.
Anyway here's some 1940s and 1950s war comics you'll find on the site -
Dell- War Comics, War Stories, War Heroes
Ace- Atomic War, War Heroes, World War III
Ajax-Farrell- Battle Report, Fighting Man, G. I. in Battle, Men in Action, War Report, War Stories
American Comics Group (ACG)- Commander Battle and His Atomic Submarine, Operation Peril (slected issues), Spy and Counter Spy, Spy-Hunters
Avon- Buddies in the U.S. Army, Captain Steve Savage, Fighting Undersea Commandos, U.S. Paratroops
Better- Battlefront, Jet Fighters, Joe Yank, This is War
Charlton- Attack, Battlefield Action, Fightin' Air Force, Fightin' Army, Fightin' Marines, Fightin' Navy, Soldier and Marines Comics, U.S. Air Force, War at Sea
Comic Media- War Fury
Eastern- Heroic Comics (selected stories)
Fawcett- Battle Stories, Bill Battle, Soldier Comics
Fiction House- Jet Aces, War Birds, Wings Comics
Harvey- Fighting Fronts, True War Experiences, War Battles, Warfront
Key- Battle Attack, Battle Cry, Battle Fire, Battle Squadron, Navy Task Force
Magazine Enterpises (ME)- American Air Forces, U.S. Marines
Quality- G.I. Combat, Yanks in Battle
St. John- Anchors the Salt Water Daffy, Atom-Age Combat, Canteen Kate, Fightin' Marines
Toby- Monty Hall, Tell it to the Marines
Youthful- Attack, Atomic Attack
Ziff-Davis- G. I. Joe
The Silver Age Sidestreet section has several examples of Charlton's 1960s war comics as well.
You'll probably also want to check out what individual issues the DCM (Digital Comics Museum) has.
I'm sure I missed a number of titles and maybe others can fill in gaps there too. There's also the matter of cross genre titles such as the romance/war comic titles which I didn't even touch on.
There are of course a number of titles which we can't host here because they are still under copyright. These would include Marvel's 500 plus war comics published between 1950-1960, DC's popular war titles (All-American Men of War, Our Army at War, Our Fighting Forces, Star Spangled War Stories) and EC's titles Two-Fisted Tales and Frontline Combat (generally considered about the finest war comics of the 1950s).
Anyway this should give you something to start with.
Best of luck with your project.
Joe