http://sdr.osmocom.org/trac/wiki/rtl-sdr has probably everything you are looking for, and more.
Apart from that, you should be able to follow the directions in the OP. You can use SDR# or more straight-forward, rtl_fm, (forget about the later, it doesn't allow to switch frequencies without restarting, but this should be possible with rtl_tcp) now with PulseAudio it should be possible to redirect the audio from those applications to dsd, but that seems to expect something like /dev/audio - I don't know how to provide that with PA.
[1] http://forums.radioreference.com/trunking-control-channel-de...
Ok, turns out there really is some additional research/instructions required to get this running on Linux…