I just put Magic Lantern on my T2i and I'm having a ball playing with it. I'm impressed with the audio options, and though I usually use a Zoom H1, I'd like to explore more in-camera audio recording.

I'm looking on Amazon for "miniUSB to headphone jacks" and I'm finding choices from $3 to $45.
Does anyone know which if any would work for me. I'm assuming it's a standard pin wiring and Canon didn't do anything weird.

Amazon.com: mini usb to headphone jack

Thanks,
Tom

Sadly those won't work. The so-called mini-USB plug on the camera isn't actually a standard USB connection. It has extra contact-points, it's a proprietary plug which just works with USB.

However, there is a brand that specializes in these kind of unique calbed, looked up the link for you:
Sescom Sescom DSLR-550D-HOCF AV Out Headphone Monitoring Cable for Canon T2i/550D DSLR & Magic Lantern USB Mini to 3.5mm TRS Female 1 Foot DSLR Audio Cables at Markertek.com (http://audio-video-supply.markertek.com/search?p=R&srid=S2%2d1&lbc=markertek&w=550D&url=http%3a%2f%2fwww%2emarkertek%2ecom%2fCables%2fAudio%2dCables%2fDSLR%2dAudio%2dCables%2fSescom%2f DSLR%2d550D%2dHOCF%2exhtml%3fDSLR%2d550D%2dHOCF&rk=3&uid=655913805&sid=2&ts=custom&rsc=8:phIT:nwF8xhgG8&method=and&isort=score&view=grid)

In case the link doesnt work, go to markertek.com and search for the 550D-HOCF AV

I just put Magic Lantern on my T2i and I'm having a ball playing with it. I'm impressed with the audio options, and though I usually use a Zoom H1, I'd like to explore more in-camera audio recording.

I'm looking on Amazon for "miniUSB to headphone jacks" and I'm finding choices from $3 to $45.
Does anyone know which if any would work for me. I'm assuming it's a standard pin wiring and Canon didn't do anything weird.

Amazon.com: mini usb to headphone jack (http://www.amazon.com/s/ref=nb_sb_ss_i_0_26?url=search-alias%3Daps&field-keywords=mini+usb+to+headphone+jack&sprefix=mini+usb+to+headphone+jack)

Thanks,
Tom

Ruben's right, it's not a standard port. Do you still have the AV lead that came with the camera? The best solution is to buy an RCA to minijack female converter and use that cable. Something like this:

Female 3.5mm Jack to 2 RCA Phono Converter Audio Cable | eBay (http://www.ebay.co.uk/itm/Female-3-5mm-Jack-2-RCA-Phono-Converter-Audio-Cable-/290598269414?pt=UK_Computing_CablesConnectors_RL&hash=item43a901b1e6)

Thank you gentlemen.

For some reason trying the a/v lead skipped my mind, probably because I haven't seen it in months! It's around here somewhere-lol.