I bike with my dogs. They run along the side of the bike not out in front. I find it much easier, especially with Bandit who thinks pulling you on a bike is unfair and stupid. Spanky loves to pull, but I prefer them on the side of the bike. I've done the out in front pulling style but I don't like it.
I didn't really do any of the suggested steps when I started. I geared up and off we went. I've had to work my way up to taking my two dogs at once due to them feeling like they are racing when we are biking. It's fun when I take my two boys. They love it.
As far as gear goes I wouldn't suggest running without a harness if you want the dog to pull. Even if you don't expect the dog to pull I'd still put one on. Bandit never pulls but he still wears his. It obviously isn't the wisest choice. If you want to do bikejoring the x back harnesses seem to be the wisest choice.
Before you set off at full speed on rocky terrain and flying over a cliff here are a few things to think about:
Does my dog know the command leave it?
Does my dog understand how to slow down?
Is my dog comfortable around a bike?
Is my dog comfortable wearing a harness?
Hope that was even some what helpful. I bike with my dogs several times a day (Bandit goes out twice, Spanky 3-4). If you have a dog who's a die hard runner they will more than likely enjoy it. It's been a savior for my boys and I. I don't think I'd be sane if I hadn't of started biking with them.
I found this to also be an amazing step by step guide to help you get started. (Hope I'm aloud to link it. If not, sorry Pit Bull Forum!)
http://www.pitbullforum.com/viewtopic.php?t=37081
ps - the dogs knowing the commands left, right, and stop really helps.