Zambia

Pants and modest shorts are acceptable for foreigners in tourist areas like Victoria Falls and game reserves. However, anywhere else I would advise you to wear a long skirt, as this is the custom of the local women. Short sleeves are okay, but keep it modest.
Linzi, New Orleans, USA

Zanzibar

While travelling in Zanzibar to avoid insulting the local Muslim women's sensibilities, try and keep you arms and legs covered at all times. Walking down the street with your knees and shoulders uncovered is akin in Westerners terms to walking down the street naked. I would also recommend light colours and natural fabrics.
Aoife, London, England

Zimbabwe

Most women wear skirts or dresses. In the capital, Harare, pants and jeans are fine, but not shorts. If you are going to villages in the country you will be more accepted if you wear loose mid-calf skirts and simple tops with sleeves. In tourist areas such as Victoria Falls dress is very casual and anything is fine.
Marg, Cambridge, Canada