NCAA Tourney - Gambling Questions Thread

Okay, so after watching the first weekend, I think Duke is beatable, and since I see the current line is Duke -7.5, I'm thinking that I might be interested in putting some money on it. Having never gambled legally before (save for a month in Mississippi post-Katrina while on detail with FEMA), I'm wondering how someone gets started into this. My thought is to post up some play money (a few hundred dollars) and bet with that until it's gone (and it will be, I'm sure). But I have so many questions for those who are already in the space:

- What sites do you find best for legal online gambling? (The legal part is important, as I hold a security clearance. If that is an insurmountable barrier, then I'm not going to start.)
- What resources do you use for information?
- I understand lines, but what is the +150, +350 notation?
- I hear there's a way to bet on two games together and move the lines in your favor. What is that, parlay? How does that work?
- What kind of prop bets do you like? What do you stay away from?
- What kind of advice would you give to a gambling n00b? What to avoid? What works for you?

And there are a whole lot of other questions that I don't know enough to ask, I'm sure. What other questions do I need to be asking myself?

Thanks in advance.
LBT, Grand Questioner ;^)