www.wwiionline.com , World War 2 Online is a pay game but you can d/l the free trial and play for like a week, its learning curve is a little steep, but really fun once you get into it. You can join the axis or allies and then decide which branch of the military you want to be in.
I would also sugest day of defeat, and the call of duty demo, that a more realistic version of mohaa if you havent already tried it out.