Recently I have been working the HELLSCHREIBER mode on 20m. visit the club site http://feldhellclub.org for more info. They have a monthly sprint and nets. but so far I have only operated during the last two sprints.
All you need is a sound card interface, pc, some free software and an hf rig.
I will update this post with links as soon as I get a few free minutes.
See my QSO from the April Held-Hell Sprint using using MultiPSK, SignaLink USB interface, IC7000 @30W, 66ft OCF up 35ft (4:1 current balun), and LDG Z11 Pro ATU. Also Ham Radio Deluxe(HRD) for rig control. HRD now supports Hell but I have verified its operation. It does work fine for PSK31 and other digital modes.