Entry visas are required by almost all nationalities, and are valid usually for one month.
Visas are not required by vistors from Egypt, Kuwait, Qatar, United Arab Emirates and Yemen. Requirements change and are inconsistent. Please double check before you visit.
Evidence of a previous visit to Israel may result in a visa refusal. Expect to spend around US$150 for the visa and wait 2 weeks. Visa rules and costs vary bewteen embassies.
Embassy of Sudan