Paul, when the pods are fully ripe they will open by themselves and scatter their seeds. you can shake a bunch into the palm of your hand. I would say they'll grow true- there isn't a lot of hybridizing going on with basil types (not that I'm aware of, anyway). I save the seeds every year.
jg

I do a lot of seed saving and some seeds heads/pods are easier to work with if you let them dry out first while with others it makes no difference or it is harder. It varies with the plant. Experience or a good book teaches you which way to go.

Also as another general rule of thumb, heirlooms and open-pollinated variety seeds produce plants much like their parents. That's not the case with hybrids. If you bought the basil as plants, see if the tag has the variety name or even if it is a hybrid. If you have the variety name you can google around for it to get the information on the hybrid or not question.

Here is an exerpt from _Seed to Seed_ by Suzanne Ashworth on basil:

"Flower racemes mature progressively from the bottom of the stem to the top. When the seed capsules start to turn brown, the stem can be cut and allowed to dry away from direct sun in a well-ventilated area. Basil plants will continue to produce leaves and flowers after the flower raceme is cut"

It goes on to talk about rubbing the dried raceme on a fine wire screen and winnowing away the chaff. BTW, I can't recommend a better book if you want to save seeds from your veggie garden!

Fatamorgana