Start teaching her to go for walks, INSIDE, in her comfort zone. After she's worn the leash and harness for a few days, pick up the leash, click (for the ease of typing, when I say "Click" I mean click then reward) then drop the leash. repeat as many times as it takes for her to feel comfortable, you may want multiple sessions.
Then you're going to move on to picking up the leash and taking a step, click her for any movement in the same direction as you. once she's confidently catching up to you, take 2 steps, then 3 then 4, slowly progressing (as long as she's still comfortable), still clicking as she catches up to you, OR if she's progressing quickly, clicking when she's beside you as you count out whatever step your doing.
Once you can walk her confidently throughout the house, move it to the back yard, go back to square one, (Clicking for one step) and progressing to a circut of the yard.
once she's happily walking beside you in the backyard, move to the front yard, and again, back to square one. You will likely have to pick her up to get her outside but you shouldn't have to keep doing this long. Once she's happily moving beside you in the front, begin on the sidewalk, and again, back to square one, at first just work in front of your house, but you shouldn't need to do that for long... you will be able to take her away from the house as soon as she's comfortable.
If she ever resists, go back a step, lower the criteria, you are moving too fast. Never correct her when out on a walk, and let her choose her comfort zone.
This may sound like alot of work and very time consuming, but you should only be doing 5 minute sessions at a time, a couple of times a day, and each step gets easier. She should progress very quickly if you keep it positive. Try to avoid her getting scared by a person or another dog, at first, until she is finding the walks rewarding in their own right.
And if she wants to stop and read the "pee-mail" let her. Make walks as enjoyable and as fun FOR HER as you can... right now, it's ALL about her!
Hope this helps!
"Reaching the Animal Mind" by Karen Pryor is an EXCELLENT read, about Clicker Training and Operant Conditioning. You will not regret reading it!