Hi & welcome to the tank.
I am just finishing my first spawn and will try to give you a little bit of information about breeding bettas, and a bit of info on the setup, but realize you need to do a lot more research than what we can answer here ok?
First, you need to know how to care for adult bettas. A male and a female cannot be kept together, they should at least be in a divided tank where they cannot reach each other or jump over (bettas jump really well). If you want them to breed, you should not let them share even a divided tank, because they may get to used to each other an not breed when you want them to.
Bettas are solitary fish, they do not like other fish around them, including the opposite sex, so when you breed them, you only introduce the female into the tank properly (there is a process) and just until she releases all her eggs, then you take her out.
Each spawn can yeild between 50 and 400 fry. My first yeild was 200 fry. You need at least a 10 gallon tank at first, with a submersible heater, bubble filter, and live plants help. You will also need a larger grow-out tank soon after they hatch (20 to 55 gallon, depending how many you have)
About 6-8 weeks after you have the fry, you will need to seperate all the aggresive fish, and eventually all the males need to be in their own seperate space or they will fight (usually to the death in tanks). Each male will need a jar that will need frequent (every 2 to 3 days) cleaning and water changes.
The fry needs to be about 5 months old before you can sell or trade them in also, so keep that in mind.
It costs around $300 in food and equipment, and about 6-8 hours a week in feeding and cleaning a week,
You can visit the following sites:
http://www.bettatalk.com
http://www.bcbetta.com