Here are the Namecheap September 2009 Promo codes:

For new domains, use the coupon code DREAMTIME.
Or, for domain transfers from another registrar, use SWITCH2NC

They also have hosting specials on this month using these codes:

SCHOOLTIME – 10% off any shared, business and reseller package
HOSTSWITCH – 15% off any shared package and business package
USE4VPS – 10% off any VPS package

I hope this saves you some money!