Learning to sing

Reznik

Okay, so, I have a goal for next year and that is to be able to sing The Trooper by Iron Maiden at karaoke.

I mean I'd like to sing better in general, but that's the ultimate goal. I can't sing particularly well right now. Basically I can do a passable rendition of Heart of Gold by Neil Young if I'm also playing guitar and I don't try and sing too loud. So how do I start not sucking?

I can't afford and don't have the time to take actual singing lessons (at least not now, I don't know what the new year will look like) so I'm pretty much stuck with self-teaching from youtube videos and doing vocals on Rock Band. Any particularly good resources/lessons/exercises to recommend?

Thanks