Gina gave some good recommendations. It's hard to help someone chose pilates workouts because what motivates one person would be a total turn off for another. Stott gives wonderful instruction & in her newer workouts she's more dynamic. Voight has several pilates inspired workouts & is quite bubbly, but it's a hybrid. Kathy Smith's Pilates for the Lower Body is excellent & would be a good starter workout. Jennifer Kriess has some great workouts that you can progress with. Her instruction is nearly as complete as Stott & she's warmer. I like Susan Deason but her instruction apparently isn't detailed enough for a beginner. Skip Denise Austin - she demonstrates poor form in the current Bicycling magazine.
You can do a search here for spinning information but the better resource is Video Fitness. Quite a few avid home spinners over there. In a nutshell, you can put a regular bike on a trainer (a stand) or buy a dedicated spin bike for a sturdier, more stable workout. The spin bikes are fairly expensive, you could easily spend $1000. But cheaper choices are available.
I just purchased a Johnny G Pro Spinner (made by Star Trac) which is a little different from the models I've used at gyms. DH is rehabilitating a broken leg & is on the spinner every morning. There are a few workout videos out, but the VF group are avid Spinerval fans. They are tough workouts. I prefer to put my heart rate monitor on & chose a music CD for my workouts. Basically like a gym spin class but I get to chose the music & have the fan on high, directed right on me!
On a spin bike, you control the intensity by adjusting the tension on a heavy flywheel. It's great training for outdoor cycling because the spin bike mimics the geometry of a real bike, unlike a stationary bike or Life Cycle. But lots of spinners never hit the dirt or asphalt, they just like the ability to get an intense non-impact workout.
And just so I don't scare anyone from spinning, anyone can do it. Since you control the tension & your cadence, you can make the workout anything you want.
Debra