For our support queue overflow and if no-one's in the office, we use Servcorp to answer our 0800.  They answer with our company name, and can redirect the call or take a message based on a whole stack of rules we've given them.  A stock standard voicemail system won't work as we still want the call answered by a human.

Having just received their last rather large bill, I'm keen to explore some alternatives.  Must be based in NZ. 

Suggestions?