I think it should be legal.
http://tasvideos.org/WhyAndHow.html
The Goal -
"We are creating art and providing entertainment."
Now Keep this quote in mind the whole time.
I agree with LocalH 100 percent. It shouldnt be considered cheating, because it doesnt actually skip any frames, but just runs each frame like it was suppose to in the first place, without lag. The only way I think this could be considered cheating is in this given scenario:
Person A does a speedrun of game X and has lets say 1000 frames total in it(I know 1000 frames would be a short game, but just try to get the concept down) WITHOUT overclocking. Person B does the same game and gets the same frame count, but the only difference is Player B overclocked his NES which gave him a faster real-life time. He got that faster real life time because where areas player A would lag, Player B would not (due to the fact that his NES runs better).
"Trying to deal with lags in timeattack is clever." Maybe so phil, but so is driving the steering wheel with your feet. Driving with your feet would require you to learn new things since your not used to it, but you dont have to drive with your feet. I perfer to use my hands to control the steering wheel, but thats just me.
If eliminating ingame lag is cheating, then using 3rd party programs/modified versions of the original emulator to manipulate the frame speed at your command and other various things, should REALLY be illegal. "The tools are not there to just overcome our lack of being perfect players, but to give us superhuman perception and godly control of the game." Sounds like cheating to me, But since our goal is provide an entertaining video, then neither overclocking, or tool assist programs are considered cheating. Now, it WOULD be considered cheating, if this sites goal would be to provide entertaining videos without manipulation of the game or the game engine of any form or fashion(also known as 'legit' speed runs, TSA is widely known and respected for his 'legit' speed runs).
Another thing that has to be done, is Like Mr. Bisqwit has done, is he has informed the public, that the people on this site do infact use these tools to their advantage. Same thing with Overclocking, you have to inform the public that you are taking advantage of overclocking and you also must know what MHZ the player clocked it to.