I have this emulator and while it isn't faultless, it's simply amazing. It's the only emulator I've seen that actually WORKS (and I've tried eight other Saturn emulators). I've tried many of my Saturn games on it and many of them work flawlessly (such as Sega Rally and the Puzzle Bobble/Bust A Move series, and others with only slight hiccups which don't affect gameplay at all (such as Daytona USA CCE and Burning Rangers, my favourite Saturn game). Even games which rely heavily on FMV such as Frankenstein: Through The Eyes Of The Monster work amazingly well in this emulator.
As Twimfy said, you need a lot of power for it (2gHz+, 3D video card) but it really is an amazing emulator. Only thing that is missing at the moment that would really make it for me is analog stick emulation.
There appear to be a number of walkthroughs on setting this emulator up on various sites, but they all appear to be very out of date. With that in mind, I've decided to write one (since I need to update the version I have anyway).
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You need the bios file first, of course. If you are searching for the BIOS files online (remember it is technically illegal) try and get all three versions, ie Jap, US and Euro. You don't acutally need them for regional issues (since the region settings are in the emulator itself), but it's best to have all three in case some games may not like certain versions (not that I've seen it happen).
I've just done a quick search on google for the bios, they're not hard to find either.
Unzip your emulator, put the bios files wherever you want. You don't need to worry about what folders to use, as you actually point the emulator to where the your bios file is when configuring it. For convience sake though, I just made a bios folder under the SSF folder.
Run SSF.EXE (this is the main executable). You will first of all get a little box with the word BIOS and some gobbledygook in it (this would be proper japanese text if you had the Japanese language pack installed). Just click OK in this box. You will then get another box with an error message and the options screen should automatically display.
The peipheral tab at the top should be selected (click on it if it isn't). Click on the BROWSE button in the BIOS section and use the standard file selection window to go to where your bios file is and select it.
While in the peripheral options, make sure to set your CD-ROM drive (if you have more than one, if you have Alcohol 120% installed it also supports the virtual drive that Alcohol uses), your external cartrige size (either 1MB/4MB RAM, for running the later SNK/Capcom releases), a backup RAM cart (so you can backup the RAM file saves (used by Saturn games) when in the Saturn's system settings screen) or no catridge, and finally the area code (region coding - set to match the region for the game you are playing).
Next, go to the Screen tab and turn Scanlines off. All the other options you should not need to alter for regular games playing, but they are there to tinker with if you like.
Click OK to exit the options, you may get another popup box, just click OK. SSF should automatically shut down.
Restart it, and you should get the Saturn settings screen, just as if you had switched on a Saturn for the first time (or replaced the battery). select your desired language with the cursor keys, and press Z to select it. Go through and set the time up as well. After this, the Saturn will go through it's normal startup sequence and you'll end up on the music CD screen.
If you want to change your key mappings for the Saturn controllers, you do this by clicking on the Hardware menu, then on Controller 1 or Controller 2 (for Saturn joystick ports 1 and 2 respectively). Just enter your new key mappings for each direction and button. If you have a joystick connected, you can use this too, as the emulator will happily accept the input (I use an Xbox pad myself).
After this, it's simply a task of putting the your Saturn game CD in the drive (or setting up the CD image on a virtual drive if using it that way) and starting the emulator. With the bios, CD drive and region selection set up correctly, the game should start just as if you'd switched a real Saturn on.
Warning, when fiddling with the options, it's best to do it with no game CD in the drive, since the emulator appears to be rather flaky when dealing with such stuff in the middle of a game. As an example, I put a Saturn CD in my drive, and had to alter the region selection, which I did, then thought I could just start the game by opening and closing the emulated CD door (done through the Hardware menu), but instead of starting the game, the emulator completely locked up, and even after forcing the emualtor to shut down, the CD refused to eject, to the point of Explorer locking up, meaning I had to reboot Windows (equally as flaky? who knows) just to be able to eject the CD. So, when dealing with any settings in the emulator (and especially when dealing with the CD/bios/region settings) it's best to do it with no game in the drive, then shut down the emulator before inserting your game CD.
Anyway, I hope the above helps you to get the emulator working so you can play some games. Have fun!
edit:some spelling corrections
