some good and not so good advice given... "flat out for 20 minutes without a warm-up" is very suspect. I believe there was an excellent guide to Turbo Training, including 4 key sessions, in the last issue of Cycling Plus written by a very talented up and coming young(ish) writer...
Beating boredom is the key thing... Ipod great either music of get some inspirational pod casts
www.ironmantalk.com and
www.enduranceplanet.com are both good . Also BBC i-player is an absolute godsend. Managed, with a combination of the above to beat my turbo trainer record and last 2 1/2 hours the other night... blowing a gale so didn't fancy the roads.
Also, totally agree about the fixed. I love riding mine. Nothing better for building cadence (should be 90+ ideally getting towards 100rpm), efficient pedal stroke and strength.. did 2 hours on the fixed yesterday... legs feel nicely worked today.