How to even out volume when layering tracks in garageband '11?

i recorded a song but there's parts where my vocals overlap so i had to record in 3 different tracks. some parts are louder than others, is there an easy way to even out the volume so it all blends together properly?

One thing you can try that will even out the volume of vocals.. Go into your edit pane, from there add some dynamic compression..this will lower and compress the level of the vocals..after that add a multiband compressor to boost the level of the vocals. also look for a peak limiter, this will insure that you stay within the -3db to 0db levels

Yep, compression is exactly what you need. Wouldnt exactly say limiting a vocal is the best idea - thats more for getting a max output, generally makes things sound a bit crap - but definitely some dynamic compression.

Essentially, compression is just evening out the dynamics in a track, making the loud bits the same volume as the quiet bits.