If you're planning on taking your car with you on vacation it's a good idea to make advance car reservations as soon as your plans are set in order to get the most convenient departure date and time.
Alaska
Alaska Ferries run from May through September and are more like a mini cruise along the famed inside passageway. You can stopover in Glacier Bay, Ketchikan, Petersburg, Juneau, and Skagway
Martha's Vineyard or Nantucket
The Steamship Authority is taking online reservations for car ferry reservations beginning January 14, 2008. They'll begin taking phone reservations starting January 22nd.
Victoria, BC
Washington State Ferries (https://secure1.wsdot.wa.gov/ferries/webres/) will start accepting Spring reservations February 29, 2008 and will begin sailing March 30, 2008.
BC Ferries leave from Vancouver, north of Seattle, about a three-hour drive. The departure terminal is called Tsawwassen and sailings are about every two hours year round.
Black Ball Transport departs from Port Angeles, on the Olympic Peninsula and arrives into downtown Victoria. Sailings are twice a day in March. Check the following link for details. They will be out of service from January 28th - February 10th for annual drydock.
Yarmouth, Nova Scotia and Bar Harbor and Portland, Maine
Bay Ferries Limited will begin sailing 2008 sailing May 30th with nonstop service between Yarmouth, Nova Scotia and Bar Harbor and Portland, Maine. Advance reservations for cars is advised.
Lake Michigan / Wisconsin
The Lake Express 2007 season ran from April 14 thru October 23, 2007. They haven't yet posted or announced their 2008 schedule but tickets will be available in the Spring. You can sign up for the Lake Express e-newsletter to be updated when the 2008 schedule is posted and reservations are opened.
Outer Banks
Reservations are only offered on the Cedar Island – Ocracoke and Swan Quarter – Ocracoke Routes. Reservations can be made up to a year in advance but must be claimed at least 30 minutes prior to departure or your reservation will be forfeited. Unfortunately reservations can only be made over the phone, not via email or the internet.
Ireland
Ireland 2008 has detailed information on ferry crossings throughout Ireland.
Mexico - Cozumel
The car ferry that used to operate from Puerto Morelos now uses the Calica pier just south of Playa del Carmen. The fare for a standard car is $80. Marítima Chancanaab (tel. 987/872-0916) has 4 departures daily from Calica at 7am, 1pm, 5pm, and 9pm. Arrive one hour before departure. The schedule is subject to change, so double-check it. The ferry docks in Cozumel at the Muelle Internacional (the International Pier, which is south of town near La Ceiba Hotel).
Greece and the Greek islands
Greekferries Club - All international ferry routes and schedules between Greece and the Greek Islands for 2008.
From Italy: (Ancona, Venice, Bari, Brindisi) to Greece (Patras, goumenitsa, Corfu) and the Greek islands (from Piraeus, Rafina, or Thessaloniki to Crete, Santorini, Mykonos, Zakynthos, Rhodes, Paros). Also to Athens, Olymbia, Delphi, Meteora, Knossos, Festos, and Lindos.
Prince Edward Island and Nova Scotia
NFL Ferries hasn't yet posted their 2008 schedule however you can sign up for their newsletter for an update on their 2008 schedule.