Please note that this tutorial shows how I made my zat holster, which is not 100% canon. The holsters the Tok'ra use on the show are great at showing off the wonderful work of the prop makers who made the zats, but they are highly impractical. The weapon has to be tied into place to keep it from falling out. So I came up with this pattern, which is a cross between the screen acurate ones and ones that can be safely worn around a con. Feel free to use the pattern or modify it as necessary if you want a more screen acurate one.
This holster was designed to be made out of veg tan leather, as it is the right thickness to make a sturdy holster out of. If you are making the holster to go with the tan uniform, this works fine. If you are making the brown uniform, you will want to dye the leather AFTER you have cut out the pieces and punched the holes, but before you start lacing it together.
Cut two of the holster back pieces out of the leather. Cut two slits in the back of one of them, for the belt to go through. Keep in mind that the slits need to be longer than the width of the belt, or you won't be able to get the belt to lace through it.
Cut one of the holster front pieces out of the leather. Punch lacing holes in the front piece, and the uncut back piece. Make sure you punch the same number of holes in both, and that they line up. The pattern pieces have markings on them for the holes to use as a guide. I have found this Hand Sewing Punch Tool to be the easiest to use. I put it on the largest setting to do the zat holsters.
If you are dying your leather, do it now. Leather dying tips can be found at the end of the Brown uniform tutorial.
Lace the front piece to the punched back piece. I originally used standard round lace for the job, because it looked good and was narrow enough to fit easily. This lacing is more expensive and more difficult to work with, but is sturdier and worth the extra effort.
Let your holster soak in water for a few minutes. Then put your zat in the holster and let it dry. The holster will hold the correct shape once it is dry.
Once the holster is completely dry, glue the back piece with the slits in it to the laced piece AROUND THE EDGES ONLY. You don't want to glue closed your belt loop. I used Contact Cement.
Here are the pattern pieces for the holster. Adobe acrobat is required, since when I had them uploaded as JPEG's different comptuers sized them differently, and they didn't always come out the correct size
Back of holster