Hej,
we made reservations for the campsites in etosha (3) and also for sesriem campsite through namibia reservations without any problems. e-mail contact was very good, quick respons. and payments could be made with credit card (fax) or by bankaccount (if you don't want to sent carddata by fax).
enjoy your stay in Namibia, we loved every part of it (solitaire-sesriem-swakopmund-spitskoppe-etosha-rundu-caprivi-shakawe (botswana)-windhoek in 3 weeks (july06)