Playing DDR (Dance-dance Revolution) on PC (and the DDR alternatives)
DDR is a fun game, but playing it on malls will cost you a lot of money. If you have a Playstation you only need to buy a Dance Pad, but if you only have PC, you'll need to do something more.
Almost any pad will do, if it works on PS I think it will work on PC
Pad -> PC Connector
Be carefull, not all pad -> PC (USB/Parallel) works. Not all of them will be able to translate pressure on two point (up-down, left-right) at once (the paralel usually works fine they said).
I don't know about other emulator, but epsxe will work fine for emulating DDR games. You will need the BIOS files to run epsxe (please check the legality for this in your country). I suggest you make ISO image of your game to speed up the game a bit, and to keep your CDROM from working to hard (and making noise that might disturb your game).
If you have a fast computer for EPSXE, you may need to limit the FPS (frame per second) of the GPU plugin to keep your game from playing too fast.
Free Alternatives: Step Mania, pydance, ttr
You can also run native PC application instead of running DDR on emulator
Windows Only. Great gameplay (a lot like DDR), it's kinda hard to find music and step files for Step Mania, but you can make one your own (and it's quite easy using the step recorder).
Cross Platform (written in python). This application is a true free alternative for Step Mania (step mania uses graphics that is very similar to DDR).
ttr (text text revolution)
This game is different from the other because it uses text mode!.