Can anyone point me to a tutorial for electronic noobs that explains how to use op-amps and what I can do with them, besides amplification?
I know it's not all online, but the Art of Electronic by Horowitz and Hill is fantastic. It's basically the only book you need for the first 2 years of learning electronics (especially if you don't have any math requirements). The second edition of the book was published back in the late 80s and a lot of the example circuits using op amps are spectacular examples.
Try Opamps for Everyone (warning -- large pdf, and some TI bias)
It has lots to teach, covers beginning to somewhat advanced topics, and it's free.
There are a couple of very good tutorials at Analog Devices and Texas Instruments. The TI one is called "Handbook of Operational Amplifiers".
This book is considered to be a key text on the subject. I dont think there is an online version available... £30 (where I come from) is around the "reasonable" price range for such books.
Falstad Falstad Circuit index has an excellent Java applet that allows you to do virtual prototyping with various types of circuits.
Has a nice section on Op amps, whats great is the built in O'scope, volt and current meters. Right clicking on a template component in the applet brings up menu where you can experiment/substitute with different values, add remove components.
Check out: http://www.opencircuits.com/Op_amp
This one helped me a lot for a Devices class which included op-amps. Really good animations, and covers most types (inverter, differentiator...) needed for a starting point.[link text]
Op Amps for Everyone (2.0 MB PDF) by Texas Instruments is a very good reference. It covers almost any aspect you might need. Even single supply opamp techniques.