I recently had the ck engine light come on my 05 toyota corolla CE...ran the scanner on it to pull up the p0741 code. I took it to dealership and thought might be related to ECM issue , they replaced it for free and wondering if thats the cure all for that code. I still notice when I put my car in reverse gear it still idles roughly. If theres still an issue with that code will the new ECM pull that code again so I know if this is a serious issue

Yeah Toyota is aware of this situation.Production changes have occurred to correct this condition.
You did the right thing to take it to the the dealership because when they pulled the code p0741 they had to apply the Toyota Technical Service bulletin TC008-04" to your vehicle.
They had to perform several tests and since you said they replaced the ECU for free it was because your vehicle was lower then 5 years old and less then 60,000 miles. This TBS is covered by the powertrain Warranty. They had to replaced the ECU with an updated unit, and that particular warranty is in effect for 96 months or 80,000 miles. Your car should be back on the road running like a champion and you should NOT have the same code again.

The code P0741, refers to a torque converter (transmission) issue.

Run a good fuel system cleaner through it. If they replaced ECM you shouldn't pull that code again, it's more like a simple dirty fuel filter or condensation in fuel.