Slice the leeks thinly.

Dice the potatoes into medium-sized pieces.

In a large saucepan, combine the sliced leeks, diced potatoes, chicken broth, and salt.

Bring the mixture to a boil over high heat.

Reduce the heat to low and simmer for 15 minutes, or until the potatoes are tender.

Carefully transfer the mixture to a blender or food processor.

Puree the soup until smooth and creamy.

Return the pureed soup to the saucepan.

Stir in the lowfat sour cream, lowfat milk, and chives.

Heat the soup gently over low heat, being careful not to boil.

Serve hot.