cable for shooting tethered

I need a longer cable to shoot tethered. do just need a mini usb cable?

Yes. But IIRC the standard for USB cables is about 5 m. unboosted; if you want to be more than that distance from your computer you'll need to either use a powered hub between camera and computer or investigate a wireless solution. If you just want the files transferred to your computer as you shoot, the EyeFi card would manage that. They now have a version that handles RAW, though I haven't tried it yet. Canon's wireless transmitter will give you full "tethered" functionality over a WiFi connection IIRC.

i checked out the eyefi but it looks like it's only SD. I need compact flash.

the canon wifi is expensive. looks like i'm stuck with usb cables. I've seen a powered usb cablethat says it can be chained up to 80'. i might give that a try.

You can get SD-CF adapters. I've got a few of them (only partly for the EyeFi card). They do work, and give you an extra source of cards if you have cameras which use SD cards as well as ones that use CF.