I've got a new bike and a newer trainer. I went with an expensive fluid one, because having a quiet trainer is important in my apartment building. It took a little getting used to, but it's a big improvement over my dad's ancient wind rollers.

As far as getting used to the pedals--it's no substitute for being outside. It can help you get a feel for the motion of getting in and out, but because the trainer elevates the bike off the floor, it's rather tall, so the getting on/off motion is different than you'll have outside. Plus, you can't coast on a trainer's flywheel but for a couple of seconds--and the pedaling "feel" is then off when you resume, so it's not a very good practice for learning how to get going and clip in, even if you can jump on the bike in a similar way as you'd do it outside.

And once you know what it feels like to clip in and out, adding the balance factor outside is another ballgame.

But as far as getting 'used' to the bike otherwise, it's great. It's helped me realize what other fit adjustments I need--the shop did some and then wanted me to try out the current setup for a while before swapping out everything. But on a trail, I was too worried about joggers, other cyclists, ipod-wearers, etc. to really figure it out. I thought I needed a shorter stem. But after time on the trainer, I'm thinking smaller bars first, plus those wedge things in the hoods for easier reach of the brake levers. And if all is still not right, then I'll think about the stem.

A trainer is good for putting on some music and tuning out the world-- something you can't do outside with other people and vehicles around.