Don't get rid of your eyebrows! I've hear horror stories. You might need to pluck your brows a little thinner, but don't get rid of them entirely.

I'd suggest you get some of that dental wax that people put on their braces (you could probably score some from your dentist or buy it for a couple of bucks at the drug store.) Hairspray your brows down, cover them with a layer of dental wax, and then cover that with makeup. I hear it works pretty well. You can also get legit costume stuff to cover eyebrows and such, but I'm a cheap-ass cosplayer so I advocate cheap-ass methods XD.

For alternate methods, check the cosplay.com forums or talk to anyone who's cosplayed Gaara; he's got no eyebrows and he's cosplayed to death.