Where can I find free online spinning or turbo classes? Ideally videos, but just audio or even an annotated playlist would do.
There's also The Sufferfest. I haven't tried these out yet as I need to get up the courage to try out my new rollers.
There are loads of plans on turbotraining.co.uk. They're text only, but if you subscribe you can use the online "player" which works really well. The audio is either supplied by digitally imported radio (trance channel) or you could just have your own music.
As an alternative, I met the guys from powerblast at the TCR show last year. They've created audio sets that have variable BPMs with the idea that you match your RPM to the music. I've not tried them myself but they seem like a pretty good idea.
Personally, I find that so long as you have a specific and varied set, and some decent music in the background, it's not too tortuous. If you try to do an hour with no set in mind then it becomes tedious as hell!
There are a number of fitness and workout music collections available on iTunes, with some offering more than a 100 pieces of music for less than $10US. The concept is you put together your own program using available music. You can also put together your own training program using available commercial music for your own use. Pick songs that have a good solid beat. For an hour program choose an introductory piece of music or pieces that give a fast paced beat that can be used with a bike on a training stand or rollers with gears set for low resistance like you were on a flat road. Increase the resistance and vary the music to match your theoretical ride -- flats, hills up, hills down, etc. We have Spinning classes in the United States and they are available in other countries as well. I recommend you contact a Spinning studio or a fitness center that has Spinning classes and take some to see what can be done and how the music is integrated in a visualized ride. A good reputable Spinning class will have you warm up at the beginning of the class and cool down at the end with appropriate controlled stretching included. Spinning classes use stationary bikes designed for Spinning classes but it is possible to set a road bike up on rollers or stand to mimic the feel. To make my bike more stable I have a training stand on the back wheel and I took a training stand that was no longer functional (I wore it out) and modified it to fit the front wheel to provide a very stable platform that allows me to not just sit and ride but also to stand out of the saddle for a more complete training session.