Torque converter lockup
Not to argue the previous comment but it's MUCH more likely to be the solenoid than the actual torque converter -if- it's a transmission related problem. If it's simply a matter of the car stalling when you come to a stop, there are MANY things that can cause this. If the car starts right up but won't go into gear, then it's the solenoid but if it's just a matter of stalling but then drives fine, other things to check would be ignition coil packs, plugs/wires, emmission system, fuel pump/pressure, etc., etc..
Now if the car starts but won't go back into gear (stalls right away) please know that problems with the lock up solenoids (or TCC solenoid) are VERY common with a number of 90's era Chevy's such as Corsicas, Berretas, Cavaliers, etc.. While there are other things (including the torque converter) that can cause this problem, including the ECM and/or wiring problems, the TCC solenoid is the most logical place to start.
Depending on the vehicle, it should be located under an access plate on the side of the trans. Raise the driver side front of the vehicle, remove the front driver's side tire and remove the wheel well access. As you are looking at the end of the trans, you should see the access cover. Once you remove this cover you should see the solenoid (please note you will need high temp "form a gasket" to reinstall the cover!).
There is a great deal of info on this both on the internet and in repair manuals. Good luck!