http://www.elite-it.com/jsp/c-Prodotti.jsp?ID=0011052

I've got one of these, cost £99.99 from the LBS, been using it last week on the boat and definately made a difference when I went out cycling last night.

The best session I did was 5 min warm up, then hard going for 30 minutes, then 5 minutes steeping up through the remaining levels and then 5 min cool down, maintaining 90 rpm. Absolutely pouring with sweat through it. Generally each session was 45 - 55 mins long.