Hi keny; There's a couple of good ones at the Fruity-Loops webpage.
To save you a few steps, here they are from my webpage:
SimSynth13SimSynth27Demo (links broken)
But let me explain what these are before you download them.
SimSynth13 is the old
freeware version that was originaly
written for Win3.x, but works fine with Win98. (Couldn't say about XP.)
Its
very basic, and works like this: You set up all the control
parameters, then "make" a wave, listen to it, then save just that one
waveform, which you'ld have to put together with others with some other
software to make a song. Obviously, not very intuitive, however, free.
SimSynth27Demo, is a
much more sophisticated unit with a small
realtime keyboard and a slick graphics interface. It has full functionality
except for the ability to save your presets. However, it does have quite
a few built in, and its relatively cheap. I believe around $20, give or take
a few sheckles.
You can program some great sounds, and sequences, and even control it
with an external midi keyboard. An all-around nice unit for the money.
Check it out.
Dex
Edit: BTW - I'm going to leave these available for download for
only a few days. (Bandwidth is money!

)
Ok . . . the links are down, but don't forget, they're always available on
the Fruity Loops page. (Or feel free to email me for them. dex4now@dex4now.com)
Edit2: One last thing. The help file for both of these is not great.
If you, or anyone else, has any questions on how to get started and save presets,
let me know. I'll be happy to help out.
(Save presets
after you've registered, of course.

)
I guess a screenshot would be nice.