Runik has released a Sega Saturn Emulator for Windows called Saturnin, heres the info from the last release:

Grab the Saturnin 0.40 Christmas release version

I've done a lot of work since the last release, you can check the change.log file bundled with the emulator for details ...
This version has sound, is way more compatible than the previous one, and is reaaaaally slow :P There isn't any sound during the bios logo due to the lack of DSP, but I assure you that sound is working (check the Cotton games in ST-V for instance )
I will work on the speed for the next version, and I'll try to release more than one version a year ...
As always, read the help file fully before emailing me or writing for info in the forums ... your answers might already be there :P
If you can't find a specific answer about your problem, there's a FAQ thread in the forums that can be updated with your input

As usual, if you want to translate Saturnin in your own language, send me back the translated str file and I'll put it online (the english version is bundled with the emulator in the langage directory).
So far italian and greek are done, and english and french are bundled with the emulator.

So that's it for now

Merry Christmas to everyone !

Downloads and Screenshots Via Comments