There are other things that can and will affect your idle if set incorrectly. Lets talk about how good is your engine tuned to begin with.

You must break your engine in and tune it properly before attempting to set your idle speed since it can be affected by both your low and high end settings. For break in you should set your idle opening enough to keep the engine running. Dont worry about your car rolling since you have to drive it anyway to break the engine in. First tune your high end needle. After doing this then adjust your low end needle. And finally set your idle speed screw. You must have a properly tuned low end in order to achieve a correct idle. If your low end is too rich it will cause the engine to load up with fuel too fast. If your idle spped screw is too high it will give you a false sense of idle and will make the engine hard to tune and unpredictable. You will have an engine that is giving you poor fuel economy because of the waste of gas while on the low end.
Here is a very good link to tuning your engine and setting your idle speed. http://www.parisracing.com/engine_tu...coversheet.htm

If this doesnt help your stalling problem, it will teach you how to tune better for sure!