There is an excellent spice company in Petaluma called WholeSpice that sells a number of Middle Eastern spice mixes, including zaatar (they spell it zahtar.) Here's a link:
You can order online and pick the spices up at the store in Petaluma or have them shipped for a fee. You can also call in an order -- the spices are ground to order:
Here's the address:
1364 North McDowell Blvd. Suite 20
Petaluma CA 94954
You might check with the halal stores around San Pablo and University in Berkeley.
I once tried a number of places for ras al hanout. I was told by one of the shop keepers
that it would be hard to find since each family had its own recipe So if all else fails:
* 1/4 cup sumac
* 2 tablespoons thyme
* 1 tablespoon roasted sesame seeds
* 2 tablespoons marjoram
* 2 tablespoons oregano
* 1 teaspoon coarse salt
Grind the sesame seeds in food processor or with mortar and pestle. Add remaining ingredients and mix well.
Store in a cool, dark place in a plastic zip bag or in an airtight container. When stored properly, the spice mixture can be used from 3-6 months.