I am a big fan of TripAdvisor. Every trip I take I make sure to read their forums and reviews about the location. They have tons of information that is just not organized that well but it can really save you when you are trying to figure out what hotel to book in the Amazon.
TripAdvisor launched a new mobile view of their website so you can easily browse the site from your BlackBerry. The mobile version is still in beta and is available in 17 countries in 11 different languages. Supposedly it also works with GPS but I could not get that feature to work.
You can view the mobile website just by heading to www.tripadvisor.com from your BlackBerry Browser. You will automatically be redirected.