I actually managed to breed my betta's once, years ago. I kept the male in a 10gallon tank and a cup of ramen cup cut in half and cleaned very well then taped to the inside of the tank so it won't float away. I kept a sponge filter in the corner opposite of the cup to provide water movement and filtration.
The female I kept in about a 2 gallon tank to fatten her up, both were fed a high quality betta food along with a 2-4 blood worms once a week. Do this for about 2-3 months for your first pair.
After the 3rd month, do a large water change in the 10gallon and only fill it about half full and put the female in inside a breeder net. Gives both time to adjust and you'll be able to tell if your female is ready or not by the way her stripes go. If they're vertical it mean's she's stressed and when first added into the breeder net she will be for an hour or two. If they're horizontal from nose to tail it mean's she's ready to breed.
Biggest thing is only let them together when you're able to keep an eye on them. I've heard horror stories of females turning around and killing the males that are 3xs their size, but the same can go for the males killing the females. Best site I can suggest for more help is www.AquariaCentral.com/forums/. It's the site I started off at when first interested in breeding fish and fish keeping in general.

I can answer more questions if any come up with breeding let me know, I'll try my best to answer. ^.^