Shameless plug:
Get "Ancient Kingdoms: Mesopotamia" from Necromancer Games (it ships in a few weeks), written by yours truly.
Change "Mesopotamia" to "Shem" and you have a nice selection of people, places and plots; including hostile desert nomads, veiled sorcerers, ancient vampires, cursed ziggurats, haunted oases, sand-worms, and more!
As the module was written for standard d20, you may have to adjust the magic levels a bit to suit a Hyborian campaign, but I can assure you that the setting in the book has a very "Howardian" feel.
- thulsa