I was surfing the web and checking my emails and I litterally stumbled upon this article at www.stumbleupon.com it is from Plenty Magazine and it is about a girl who stopped washing her hair! No kidding, I could not do it but after you read the article you might try it. If you have curly or wavy hair at least. CLICK HERE to check out the article, if it works for you think of all the money you would save on shampoo. Not to mention time in the shower, oh and even water because your showers would be shorter.
It is supposed to work better with curly or wavy hair, since I have straight hair I do know it won't work for me. I tried last winter to not wash my hair but 3 times a week, and I really looked like a grunge girl from the nineties. I have oily hair and I have to wash it. This could work for you though and she has some good tips in the article.