Hey guys, I'm planning on recording a new song for my solo project and for the vocals during the verse I want to have my voice sound different, like with an effect on it. The type of sound I want is like what Billie Joe's voice sounds like on the verses of American Idiot, it sounds like it has some reverb and maybe a little bit of a like megaphone sound. Also on the Green Day song Holiday, during the bridge it sounds like he has a megaphone sound. I like the sound more on American Idiot though. I'm not a huge Green day fan or anything they were just the best example I could find on short notice. So my question is, I'm using Line 6 gearbox and I'm wondering if anybody could help me get a good overdriven mic/megaphone sound without it sounding too distorted or anything, I just wanted a subtle sound to it. Thanks a ton for any help.
The megaphone sound is a popular request.

Roll off everything under 1-2Kh and everything over 4-6Khz. Compress the crap out of it and run it through an overdrive plugin. Done.