Some people think that the Tool Assist is a cheating device, which help to go through enemies, go through walls etc. Ths is not correct. Almost every emulator can do a Tool-Assisted Speedrun. Even if you think that chaet codes are used, not. Using cheat codes violates the rules of the TAS (Tool-Assisted Speedrun).
Which emulators can do it?Edit
ZSNES License: Free
1. My favourite emulator.
2. Starnge enough, not prefferd for TASes in www.tasvideos.com.
Snes9x License: Free
1. The best emulator for TASes.
2. Not my favourite one, but still like it.
Spoiler warning: The text below may contain spoilers! If it does, you can help by fixing them.
FCE Ultra (a.k.a. FCEUX) License: Free
1. My favourite NES emulator.
2. The best emulator for NES TASing.
VirtuaNES License: Free
1. I haven`t tryed this emulator.
2. Acording to www.tasvideos.org, you are not allowed to do TASes with it.
Spoilers end here.