isiXhosa is one of the official languages of South Africa. There are 7,907,153 (17.64 %) first language speakers [2001 census data].

isiXhosa is a member of the "Nguni" language group, and is most closely related to isiZulu, isiNdebele and SiSwati.

isiXhosa (Xhosa) language family tree.

Books

English-Xhosa Dictionary (Arnold Fischer)
[ Buy from Kalahari.net | Buy from Amazon.com ]

The Greater Dictionary of isiXhosa. "A comprehensive trilingual (IsiXhosa, English, Afrikaans) dictionary that promotes multilingualism and indigenous languages was launched on the 22nd of September 2006, at the University of Fort Hare."
[ Nutrend (publisher) link ]

South African Oxford Multilingual Primary Dictionary (Nguni) (OUPSA)
[ Buy from Kalahari.net | Publisher link ]

Proverbs

• 
  Xhosa Proverbs (Zolile Calana)
  [ Buy from Kalahari.net | Buy from Amazon.com ]

• TRANSLATION SERVICES TshwaneDJe Language Services (Translation, Proofreading, Editing, Transcription and more, for all official South African languages and most major world languages).

• Umhlobo Wenene FM

Language courses

African Voices
produces multimedia CD-ROM lessons for isiXhosa and isiZulu. These can be ordered directly from African Voices in South Africa, or can also be purchased from Amazon:
Speak Xhosa With Us (Book & CD-Rom...)

Teach Yourself Xhosa Complete Course...

Projects

http://www.translate.org.za/
A non-profit organization translating various OpenSource software packages such as OpenOffice.org and the Mozilla web browser into all official South African languages. They have released isiZulu, Sesotho sa Leboa and Afrikaans versions of OpenOffice.

isiXhosa Wikipedia

Miscellaneous

Google in isiXhosa