Question: 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?

Answer: 
Hyperphysics has a pretty good section about opamps: 

* [Operational Amplifier Concepts](http://hyperphysics.phy-astr.gsu.edu/hbase/Electronic/opampcon.html)
* [Op-amp Varieties](http://hyperphysics.phy-astr.gsu.edu/hbase/Electronic/opampvar.html)
There are a couple of very good tutorials at Analog Devices and Texas Instruments.
The TI one is called "[Handbook of Operational Amplifiers](http://focus.ti.com/lit/an/sboa092a/sboa092a.pdf)".