Is it really true that anyone can sing, with some practice?

I'm a bist/guitarist and I really want to start singing. I play all genres, and I write songs a lot, I just want to be able to grab an acoustic guitar and show my basic ideas to people, and get opinions. The only drawback it that I scratch my throat a lot, because of allergies. My regular voice seems fine, but could I have damaged it already? Also, as a follow up question, do you know of any good lesson videos online? I want to get started correctly, breathing through my diaphram, before I start practicing songs.