How would I go about renting my house out?

Okay, so I'm only 22 years old, and my husband and I bought our home 2 years ago. Well, we are wanting to buy something a little newer and on a better side of town, so we have been making plans to sell our house and buy another one. Well, I started thinking about maybe renting the house out. I was just curious as to how I would go about doing that? Such as what are some laws I would need to know about, or do I need to have a permit to rent out my house? Also, do you think it would be a problem getting another mortgage for our new house with our old one still on our credit? Again, we are only 22 years old, but have EXCELLENT credit, but being young I know they might say we dont have enough history in order to obtain two mortgages.. What do you think I should do? Rent the house out, or just sell it and get my money back out of it? Also, I live in Houston Texas, and the house I currently own and live in was a foreclosure, so we got it for about $55k, and the houses in our neighborhood are going for $100k. So since the house wasnt that much, would if be a problem if we wanted a house for around $150k?