I would like to list here a few webpages, which I strongly recommend to visit.
There are already QRP clubs almost in each country: the "crazy people", who transmit with 5 or 10 W around the world. And they also still united in clubs. Unbelievable (hi)!
If you have already envisaged to build a transceiver by yourself, those QRP rigs will surely be interesting for you. Get to know everything at the DL-QRP-AG (German Working Group for QRP and Self-Construction, in German) about availability of kits, tips and tricks i.e. in the FAQ. The DL-QRP-AG also shiped until 2015 every 3 months the magazine "QRP-Report" (Directory as PDF) to its members.
Other QRP clubs: