Here is some information on Tahiti for a cruise: http://cruisecritic.com/ports/newport.cfm?ID=36 This is one of my favorite sites to get information, ideas and reviews before getting into the booking stages with my Travel agent.
As for agencies, I have been using http://cruisingco.com/ for several years and never been happier. They are wonderful, quick, very knowledgeable, I don't know what more I could ask for.
My main suggestion is to just stay away from the "online discounters" I have found that my agent is usually able to get a better rate and I don't have to worry about having problems with the booking when she takes care of it. The same can't be said with sites like Orbitz, Expedia, etc.
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