freestompboxes.org

https://www.circuitlab.com/

Supposed to work in the browser cross platform.

That looks like it may be quite useful, thanks for the headsup.

That looks pretty cool - Very easy to use.

Anyone got a split supply opamp circuit working?
I'm trying out a high pass sallen-key filter.. no luck with a split supply and Vref..

I tried making some basic filters using http://www.DoCircuits.com. Liked the look and feel of devices they had. Still early though. Maybe you guys can give it a spin as well.