As a triathlete I do lots training on my indoor trainer, often in the form of a run-bike session, and I find that the spinning definitely helps my running in 2 ways: 1 is that it aids running fitness, and 2 is that it helps running technique - when I run immediately after a fast spin I find I have good leg speed = more efficient.
I usually warm up for 10-15 mins on the indoor trainer at high revs (100+) prior to a run from home.
The first few times will be harder because you aren't used to the technique, but stick with it and I'm sure you will feel the benefits.
Martin.