I was glad to see that Michelle Malkin and others are distressed by immodest dress. IMHO the subject of modest dress can be split up into two separate subjects: "How" and "Why". As for the the "Why" I saw an excellent article by Dina Coopersmith at aish.com. As for the "How", this matter is covered extensively in Jewish Law. The "Biblical Garden Clothing Collection" has a summary of these laws.