Emulators on phone?

Hey guys(and girls), I was wondering if it was possible to run an emulator on a phone(like a samsung intenisty or lg octane or lg cosmos), the last two phones are the possible phones Im going to be upgrading to, and the intensity is the phone I currently have. Anyway, I was just wondering if it was possible to run an emulator(like GBA or SNES or something) any help would be much appreciated oh and please tell me if I would have to do something hackish or something risky to the phone. Sorry for the essay
Answer #1
Depends on the OS the phone runs.
Answer #2
With android, you can use: Nesoid, Snesoid, Gensoid, N64oid, PSX4droid and Gameboid
Answer #3
Yeah but unfortunately none of the phones listed are Androids, I dont have the money for a smartphone