some craft stores. like michaels have a section with leathercraft items. You need either a leather punch or a special needle like 3littlebirds said.
bumping this, I need to repair some jackets around here (yeah... the veg head has to repair the leather...that sucks) mostly pocket rips. THese are thinnish leather, a 70s blazer cut and a suede bomber style (not the useful bike type) special needle, check, but what about thread? can dental floss work? it is much cheaper than carpet thread (or is there a middle ground I'm not seing here?) thanks all!
I'm not too sure about the thread, but the curved needles work best. It seems to me that you can buy a straight needle or an almost circular one and the round ones are a lot easier, especially if the jacket has a lining.