The printed version of the UN Telephone Directory (in pdf format) is now available in e-deleGATE, the secure portal for Permanent and Observer Missions. The information is listed under "Resources / Telephone Directory / Yellow Pages."
Information on Permanent Mission addresses and delegates' contact information in New York is available in the Blue Book (no password required).
For Geneva please access: Permanent Missions in Geneva.
NOTE: PDF documents are searchable by pressing CTRL + F.