The hotels will help you connect with phone lines. Most everyone in Israel understands English. It is up to you - you know your own spending habits and budget. We recommend that you bring a bundle of 100 single dollar bills, per couple. They will be useful for all kinds of things like bottled water, postcards, ice cream, stamps, bookmarks, souvenirs, etc.
Most credit cards are welcome, as are traveller's cheques.
You really won't need much cash, since breakfasts, dinners, special meals, tips, and fares are covered in your fee. These can be purchased at Wal-Mart. Israel's power is 220 voltage. Yes, bring a couple. Be sure to bring a Bible with Old and New Testaments, and then you might want to tuck away a small Bible in your pocket or purse.