When you fly into Aruba you will be landing at Queen Beatrix International Airport. There are a variety of ways to get around the island and you can rent a motorcycle, scooter or car. There is also a departure tax from the Airport, around $36.50 (it should be included in the price of your plane ticket).
There is taxi service all over the island as well. One great travel tip - some web sites will tell you the average fare of your taxi ride from the airport to a given location. Additionally, your Aruba resort may have the typical fare (or better yet a free shuttle!)
With anything you do on your Aruba vacation, figure out what you should be paying and make sure that is what you pay! There are a lot of people out there who are waiting for an ignorant or naive tourist - don't be one!