Sounds like the N95 adapter may be a better bet, but if you want the OEM power pack, it is the Nokia AC-4U. It is available at many web stores and here is a link to the Amazon.com page ($4.68 + S&H at one of their affiliates or $20.18 from Amazon, shipped free):
http://www.amazon.com/Nokia-NOTCPAC4.../dp/B000FTG6EA