Nothing special, just a few, especially in French :
- bentocaz (in French), a French site for selling / buying 2nd-hand recumbents (bicycle that places the rider in a laid-back reclining position, as my trike) – got mine through this site ;
- the “Forum du Vélorizontal, vélo couché et autres véhicules à propulsion humaine” (obviously in French), an active forum about recumbents ;
- velotaf (in French), and especially its forum (even one part on “vélos couchés, trikes et velomobiles“), a French site for bike commuters.
- Commute by Bike (in English), quite large amount of info (I recommend the “Guide to a Simple Bike Commute“, sharing some essential tips).
- Bike to the Future (in French), site from a vendor, but with many non-commercial and general information about trikes, recumbents, and other kinds of HPV (Human Powered Vehicules). To bad to get into that stuff only now and not before, as these passioned guys are located in the Canton of Neuchâtel, where I come from !