This is the usb-dvb-t device mentioned on this site - I've blogged about using it under Ubuntu before but things have changed for 3.x kernels, and I'm using Arch more and more now. This might all be redundant when 3.2 kernels arrive - since the driver is in the kernel tree.
I wasted a whole evening following the instructions linked from the above site to get the v4l drivers going. No joy under Arch - the process worked but I got all sorts of 'disagree with symbol' errors, and it hosed the drivers for my dvb-s device. I had to do a 'make rminstall' in the v4l source - and then 'pacman -S linux' to get my original Arch drivers back (I'd deleted them since Arch uses compressed modules, and that was sited as one of the potential sources of the errors). I also did a 'pacman -S v4l-utils' - but I don't think I actually needed to...
So I went back to the non-v4l driver. I downloaded this (for 64bit in my case) This is meant only to support kernels up to 2.6.39 - but adding:
ifneq (,$(findstring 3.1.8,$(CURRENT)))
@cp -f v4l/kernel-3.1.8/* ./
...to the Makefile, and copying v4l/kernel-2.6.39 to v4l/kernel-3.1.8 I managed to get it to compile. I failed at the this installation, but I copied the 'dvb-usb-it9135.ko' to '/lib/modules/3.1.8-1-ARCH/kernel/drivers/media/dvb/dvb-usb' modprobed it, and Kaffeine picked it up without even restarting it...cool!