Hey buddy,
Here's a couple things to add to what Tim has said.
Be honest, CONFIDENT, and as much of a no brainer as this sounds Sell yourself to them. Offer up things, small talents and experiences that don't make the Resume.
Keep answers direct and short but complete. It's not a BS'ing session.
If they ask you for a piece of information that you don't have, Always, as corny as it sounds, say I'm not sure, but I can get the information and get back to you on that. Don't guess cause if you guess wrong it's game over. If they actually want the info, GET IT and get back to them.
These are things I've learned from sitting on both sides of the interview table.
I'm guessing that due to the time it's a phone interview, so try to sound enthusiastic about it even though it's tough given your circumstances. If your already getting an interview chances are that they see something they like on your resume. Try to get that out of them and elaborate on it.
Good Luck