jbt - The international airport is on the south end of the island and Rodney Bay is on the north end. Big jets fly into the international airport. There is a smaller airport in Castries but it is only for regional planes. The trip from the south end to the north end usually takes around 1.5 hours and taxi costs vary a lot but are something like US $75-$90 because it is so far.

As SunsetSammy said, Rodney Bay is a good place to stay and you will find everything you need there with side trips all over the island by guides. A climb up the easier Piton is a fun time too if you are up for that.

St. Lucia can't compare to Sint Maarten in terms of night life or level of activity but it is special in its' own way.

Enjoy your trip!