General: an organised tour is a good way to see a large number of the endemic and near endemic species in Namibia. Many people however make their own travel arrangements and this is perfectly feasible.
Flights: a selection of major airlines fly into Windhoek, but it is sometimes cheaper to fly to South Africa and then either drive or fly onto Namibia. South African Airways and Air Namibia operate daily flights between Johannesburg, Cape Town and Hosea Kutako International Airport, 42 km east of Windhoek. Air Namibia also flies twice weekly between Windhoek and Harare, Victoria Falls, Luanda, Lusaka, Maun and Gaborone. There are regular direct flights from London and Frankfurt to Windhoek. Air Namibia also operate internal flights between Windhoek and the major towns in Namibia.
Visas: you should check with your local embassy and / or its website for visa requirements. In 2005, visas were not required for visitors from the UK and South Africa.
Vaccinations: your local doctor should be consulted about health matters and the range of inoculations which is advised.
Travel: this is best done within Namibia in a private vehicle as public transport is limited and the distances are vast making travel rather slow. The road infrastructure is good throughout the country and most destinations are well marked on maps. Bus services are limited to a few luxury coaches that connect Windhoek to Cape Town and Johannesburg, but local minibuses run up and down the B1 from Oshakati to Keetmanshoop.
There are border crossings from Botswana, Zambia, Zimbabwe and South Africa and bus companies service these routes. Driving between South Africa and Namibia is quite comfortable on well-made roads.
Cars can be hired in Windhoek and at the airport. You should consider what type of vehicle you will require as travel to birding hotspots and around reserves may be on gravel roads where a 4WD and / or vehicle with a high ground clearance can be useful. For travel in desert areas, make sure that you have plenty of water, spare fuel and provisions.
The Trans-Namib Railway operates a reasonable service that connects most major towns. The trains are reliable and carry economy and sleeper classes, and if you're not in a rush they represent a pleasant and inexpensive - if extremely slow - way to see the country.
Currency: the local unit of currency is the Namibian Dollar the value of which is pegged to the South African Rand. South African notes and coins are accepted in Namibia and often received in change. There are several banks with ATMs in the centre of Windhoek. Travellers cheques, foreign currency and major credit cards are also widely accepted.
Guidebooks, travel companies and websites provide much of the advice one needs, but key points warrant repetition here: (1) be aware of the risk of malaria and seek current advice, sleep in a sealed tent or under a net and take prophylaxis as recommended; (2) always ensure you have sufficient water and some method of purification (even if this comprises a pot and a campfire for boiling); (3) do not underestimate the danger of being in the sun for too long, ensure you use sun-block, drink plenty of water and wear a hat; (4) be aware of the risk of AIDS; (5) ensure that you take a reasonably-equipped first-aid pack with you including supplies of hypodermic and suturing needles. See the following 2 websites for the latest safety and travel information: US Travel and UK FCO.