Homie just means friend, pal, buddy. I don't think it's gender-specific- I've heard people call men and women homies. This is kind of a loaded question. I've seen a lot of Mexicans and African Americans use this word, as well as people of any ethnicity that listen to a lot of rap and hip hop and R&B. Anyone can say it, though generally when people you wouldn't suspect enjoy rap or hip hop and R&B do, people tend to think it's kind of funny.
"'Sup, homie?" "How's it hanging, my homies?"
Variations: homie g dog, holmes, homeslice, homeskillet.
Disclaimer: It wasn't my intention to insult or offend anyone.