Sheeeet.. I've been using Dove, unscented soap to wash my scalp for years. Keep my hair short.. works better than regular shampoo.
For those who'd rather trade FRN's for shampoo-in-a-bar; JR Liggett shampoo bars Not affiliated, just a happy customer.
I meant to post this earlier in the year but just now got around to it. Like NSS, I'm not affiliated, just a happy customer. They sell at the local farmers market (in the craft "shed") on Saturdays. Head to Toe Shampoo and Body Bar Soap All of their soaps are handmade in small batches. I've used some of their other soaps as shampoo as well and they foam a little more than the "Head to Toe" but work just as well. If they made dishsoap I wouldn't have ANY soap in my house that wasn't made by these guys. *ETA* Forgot to mention that we use their natural bug spray too...it's awesome.
I also use Dr. Bronner's Castile Soap. Making your own soap is also fun, but be cautious when using lye --read the warnings and be careful.
@Brokor -I've been meaning to learn how to make lye soap but just haven't taken the time. I agree that you need to do it right and be careful though (with the lye).