The client can be found here: http://code.google.com/p/dl-fldigi/ , at
present you'll need to compile from source with one small change to
the makefile after running configure on your machine.
A quick guide:
1) Grab the source: svn checkout
http://dl-fldigi.googlecode.com/svn/trunk/ dl-fldigi
2) cd dl-fldigi
3) ./configure
3a) install any missing libs (you are going to probably need
portaudio, libsndfile, libsamplerate)
4) install libcurl
5) edit the makefile in src/ , line 412 on my machine need to swap
-L/opt/local/lib -lsamplerate for -L/opt/local/lib -lsamplerate -lcurl
6) make
7) make install
8) run fldigi, remember to enter your details in the operator tab of
config and also select a payload to track in the DL tab of the config
9) tune into the signal and it'll start uploading.
It might be easier to wait for the binaries :-D
James