Take it one day at a time.
Start out slow.
I bought a bunch of dvds and work out in my house. My favorites are Jillian Michaels Ripped in 30 and Shape - Hollywood Workout.
Shape's workout is 2- 20 minute exercises you can pick from and 2 - 10 minute exercises you can pick from.
Ripped in 30 has 4 workouts. You start with Workout 1 and graduate to workout 2 and so on with each passing week.