I just formed a band, and I'm rhythm guitarist and backing/ occasional lead vocals. The thing is, I'm not really a singer(except when I'm blaring the music in the car on the highway ) We're writing originals and covering some songs from RHCP/Foo Fighters/Nirvana/ etc. etc. etc.
Question: What exercises/ warm-ups do I need to know about? How do I/ how do I know I'm staying in the correct pitch?
BTW, I have a pretty deep voice.(Our RHCP covers are gonna be mad lolz with me doin John's vocals )

The first thing I would recommend is get sonme lessons with a qualified coach. Even if it's just a few lessons. They can really point you in the right direction and let you know if you are doing the exercises correct or not.

it's easier for a coach to explain things in person becasue voice is about feeling and sensations. With that said, I great exercise to work on relaxing your voice is to sing with your tongue sticking out on the vowel sound "ah". You want to keep the sound connected and not go "ah" "ah" "ah" on every syllable. This will start to release tongue tension that a lot of beginners have. You can then stick you tongue back in and sing on "ah" again. This should feel a bit easier than with your tongue out.

Then go back to the lyrics you are tryign to sing.