By ship
Manado has a harbour with ships going to and from the more Northern Islands Sangir Talaud area.
Bitung is the major port of North Sulawesi and you can get on board a Pelni ship to sail towards other area's of Indonesia. Some of the larger cruise ships that travel from Australia towards Thailand or other Asian countries also make a stop at Bitung.
By plane
Manado has an International airport with numerous flights a week to Singapore, Kuala Lumpur, Davao in the Philippines, and just about all the big cities in Indonesia.
Air Asia, Asia's budget airline now run three flights a week direct from Kuala Lumpur to Manado [Update as of October2010 this Service seems to be terminated/suspended]. Silk Air run direct from Singpore but a quite a lot more expensive.