Has anyone lost weight with walking as their only exercise?

Everything is down to calorie consumption, so you can even sit and do nothing and still be losing weight assuming that you are on calorie deficit. But it's an advantage for you if you do exercises, because you improve cardio endurance, strength, tone-up your body, improve health in general etc. depending what sort of exercises you do and how regular. So the answer is yes, you can lose weight while only walking, but if you will be consuming more than you burn (no matter how long and fast you walk) and will be always above your calorie maintenance level, then you won't be losing weight but gaining weight.

I used to only walk as exercise and with controlled calorie count for diet I lost weight. Now that I am smaller I still walk but it doesn't get my heart rate up enough even fast walking to burn as much calories.
I am thinking of stopping my gym membership for the summer since I hate working out inside when it is so nice outside. I thought about just walking and then using my bike to get my exercise along with all the yard work and push mowing I do too. I haven't decided what to do yet though.
Good luck!
If it is bad outside, you can use the Leslie Sansone Walk Away the Pounds dvds to walk to inside in your house on level ground. I used to do those all the time at 5am in my PJs for the last 5 to 7 years or so and we used to do them at my office during our lunch hour too.
I try to get a 1-2 mile plus walk in during my lunch hour in about 20 to 30 minutes outside now when the weather is good around my office area.