www.learningthai.com is a pretty good way to get started. You can click on various words/phrases and hear it spoken so you can learn the tones.
I have been going to 1 on 1 tutoring for a few months and I can speak a fair amount but I'm not great at understanding it yet. In another few days I'll have finished the basic reading/writing course. I'll be able to read but usually won't have a clue what it means!