I like the Navy Seal Workout found in this book. This book starts you where you are at and helps you build your fitness. You can find it for as cheap as $2 at Amazon.com.
For instance for pushups they suggest pyramids. Here's how they work:
1) 2 pushups- 15 sec rest, 4 pushups- 15 sec rest, 4 pushups- 15 sec rest, 2 pushups.
2) 2 tricep pushups- 15 sec rest, 4 tricep pushups-15 sec rest, 4 tricep pushups-15 sec rest, 2 tricep pushups-15 sec rest.
3) 2 divebombers-15 sec rest, 4 divebombers-15 sec rest, 4 divebombers-15 sec rest, 2 divebombers- 15 sec rest.
4) 2 wide pushups- 15 sec rest, 4 wide pushups- 15 sec rest, 4 wide pushups- 15 sec rest, 2 wide pushups 15 sec rest.
This is a beginning pushup routine. If you can handle more then do more to start.
They also have a multistep plan for building your abs and lower body. Of course they have running routines too.
I know "Navy Seal" sounds intimidating, but this book does a good job of starting at the ground floor and help you build up. Go at your pace.
I worked at this when I was in my 40s and fat and was amazed at how much progress I made quickly.
http://www.amazon.com/Navy-Seal-Wor...r_1_20?ie=UTF8&s=books&qid=1247458269&sr=1-20