I've been following Tracy since Tim launched her as well, and I'm so glad I did. It was easy to find an RKC in my area to teach me the swing and then get some kettlebells of my own. Tracy is correct in saying that you only need a 4x6 space to do your swings. This is by far the most efficient exercise I've ever done, and I'm a swimmer. I saw results within two weeks, and by seeing I mean that my arms looked better, my waist was smaller and while washing myself in the shower I was finding muscles I've never had before.
I would recommend you learn how to swing first from a professional RKC, I've seen plenty of people in my class that took several days if not several weeks to "get" the swing. Once you "get" it, it feels natural and as everyone agrees, it's a lot of fun to do. But don't mistake fun for easy, it's a lot of work, but it is very rewarding. Again, I would stress highly that you should get an RKC to teach you the proper way to swing, they have amazing pointers and some basic tools that put you in the correct swing form. The mechanics of the swing are nothing like you think they are, both my husband and my brother got it wrong when they were watching kbell swing videos, and so did I. Only after I met with the RKC did I really understand the motion. I know you'll have your "AHA" moment too if you do this properly.
I started with the 8Kg kbell, but outgrew it in less than 2 weeks. You have to start with a lower weight in order to practice the swing until you feel confident doing it. I now use my 12kg for most of my swings, be them double or single handed swings. I also use a 16kg for mostly lower rep double handed swings. Shopping for kbells is an experience. I bought what was available at first, but because my RKC has some amazing kbells, I invested in better ones once I felt I knew what I was doing. Not all kbells are created equal, so I would recommend having that discussion with your RKC as well. Kbells are not cheap and the shipping costs can be as much as the kbell, so keep that in mind. If you get them from a sports store, make sure to swing them before purchasing, some of them have weird coatings that slip our of your hands, some of them have a very rough finish that could destroy your hands.
Food is very important, something I'm still not very good at, but getting better and better. Tried some of Tracy's recipes from her blog and they are delicious and highly nutritious.
I'm definitely a kbell swing believer, for life.
Buy this book, invest in some training with a local RKC, buy some kettlebells, eat as advised by Tracy and watch your body transform.