before speaker, after amp? can you tell me what it is?

My friend told me about this product that you plug your amp into, and it sends the direct feed to your recording software/interace. You take the 1/4 inch cable that plugs in to the speakers and plug it into this device. Then you take another send from the box and plug it into your speakers, and mic up your amp. So you have a direct send from your amp, and a mic send from your speakers. he said he has heard that it is a great way to record guitar, but doesn't remember what its called What is it called!??!

does it even exist?

DI box (http://www.soundonsound.com/sos/jun02/articles/diboxes.asp)?

Here are a few approaches:
1 (https://taweber.powweb.com/store/balun.jpg) (note: Weber sells the needed 1:1 transformer - part #WBALUN)
2 (http://www.tube-town.net/diy/di-lineout/LineOut.jpg) - basically the same as above with a ground lift.
3 (http://www.charlestongolf.com/lineout/) - Firezog and other stuff

Yes a DI box. The Palmer PDI-09 is such a product for example-- http://www.palmergear.com/pdi09.shtml Of course there are others.

You can also use it without an amp, into a computer interface, which might improve the sound you get that way, I think it does.

Here's a youtube demo

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As you are aware, you still have run your speaker or it will kill your amp. But there are attenuators that have a dummy load feature that will allow you to record silently.

http://www.youtube.com/watch?v=kz3E11y01DM

Found it, Radial JDX amplifer DI. I didn't know you could use a DI box in between your amp and speaker, looks dangerous. I'm gonna stick with a mic, thanks for your help!

It is common to run a DI before the amp.... it has parallel inputs, which means that it is in and out... and then xlr to the board or pre

DI's require phantom power unless you get an active one, which will require a battery or wall wart

guitars will not sound as full or rich as through the amp, but this can be used in your favor.... you can use the very clean signal to drive effects and then blend the amp in to get the color you want.... as well, with proper placement in the stereo image, you can get a nice sound that is "thicker" than a single input

There are tube DI's, too, if you want a tube sound. REDDI and Radial Firefly are the two that come to mind.
A number of bass players are using them since the signal can be ran into the PA for the house and still get a nice sound through the monitors, without having to bring an amp. I haven't tried one but it looks tempting.

Some Weber mini mass attenuators have a line out and they go in between the amp and speaker. You could just use the line out function and not attenuate the volume.