Ghana Visa and Immigration Control
Other than some from other West African states everyone requires a visa. These can be obtained on arrival, but this is usually for those flying in from places where there is no facility to obtain a visa, its unlikely that you could fly out of a UK Airport without a visa.
You can get a Visa from the Ghana High Commission in London, both by visiting or via post. They say it takes 4 days when visiting in person and to allow up to 10 days by post. (You need to plan to have your passport away for this time).
You need a visa to visit the country, but you need to have hotel reservations and a return air ticket to get a visa.
They don't take cheques or credit cards so its money orders or postal orders.
You can download a form and other details from:
Further information is available at: http://www.ghanahighcommissionuk.com/passports_visas.php#visas
You can get links to other country sites from: http://www.touringghana.com/visas.asp (This however contains many errors).
The visa is a printed page that they stick into your passport.
The only other requirement is that you have a certificate showing you have been inoculated against Yellow Fever. See health
Immigration control and formalities
On arrival, you have to fill in a small card, information includes your passport number an address that you are staying, as well as the purpose of your visit.
You have to fill in all the spaces, even if it doesn't make sense to you. Its no good explaining you are taking a car and touring they insist on having at least one hotel filled in, so make sure you have at least a couple of hotel addresses with you.
Also make sure you have a pen with you or you will need to borrow one off another passenger.
In theory you have to have an inoculation certificate showing you were inoculated against Yellow Fever, but they didn't ask to see it from anyone when I arrived.
Customs has a red and green channel.
On leaving, you have to fill in another identical card. This also has to have at least one hotel where you stayed listed, so if you pack your receipts make sure you can remember at least one place where you stayed. They won't let you pass until you fill something in the box.
Passports get checked a lot of times when you are leaving, I counted 7 times, so keep it out until you get to the departure gate.
Security scanning and the like is efficient and competent, and as at December 2008 you cannot carry bottles of water past the scanning machine. Given that its hot and you may have several hours to wait until the time you get on a plane and get given a drink, night time flights are advantageous, as its cooler then.