In replacing a wall switch which runs to three switched outlets - Original switch 20 yrs old appears to be standard single pole - Now switch does not turn outlets off Any ideas what is wrong?

If the switch is ALL you replaced, and if you hooked everything up EXACTLY like it was before, then it SHOULD work. Therefore, I suspect you got something wrong. How many screws are there for wire connections on the new switch? On the old switch? A single pole switch will have only 3 connection screws (counting the ground connection), while a 3-way switch will have 4 connection screws. (Also, a single-pole switch will have labels for "On" and "Off", while a 3-way switch will not have these labels.) Did you replace one or more of the three outlets? Did you wire the new outlets EXACTLY like the old ones were wired? Dig the old outlets out of your trash can and look closely at them. There should be a little metal tab connecting the two screw plates on each side of the outlet. Has this tab been broken off on either side of the old outlets? Is there a red wire anywhere in this circuit, and if so, how is it connected at the switch and at the outlets? Did you put any other devices on this circuit? If so, how are they connected? Something is not exactly the same as it was before. And I can't help you until you tell me what that is.