Apple quietly pulled the eMac from the consumer channel, and is making it available only through the education channel. The change happened on October 12, during Appleis "One More Thing..." event. The eMac is conspicuously missing from the Apple Store, but is still listed at the Apple Store for Education.
The eMac was originally targeted at educators, hence the "e" in eMac, but became so popular that Apple eventually made it available through regular consumer channels as well. With the Mac mini and new iMac in place, the eMac may not have fit in Appleis retail strategy any longer.