If you are going to Malta and you enjoy a little exploring, I highly recommend taking a trip to Gozo, a slightly quieter island than that of Malta, and beautiful in its own right. The ferry to Gozo (Mgarr) from northern Malta (Cirkewwa) runs regularly (24 hours a day in both the mid and summer seasons, which are listed as the May 30 to October 29 for 2006). The trip is both quick (25 minutes) and inexpensive.
When on Gozo, there is a bus system, but they do not seem to run as regularly or as late (to some of the destinations) as they do on Malta. Buses from the port of Gozo to other sites leave only shortly after the arrival of each ferry and is loaded with people. The bus goes to Rabat (also known as Victoria), the main city on Gozo. Go to the tourist office near here (signs are vague, but locals are extremely helpful) for a bus schedule and walking maps of The Citadel.
The Citadel (entrance is free) provides fantastic views of the Gozo countryside and allows visitors to get an idea of the size of this island. Walk around the highest points of the fortification (on top of a hill) and see the Mediterranean in the distance.
The bus going to the Blue Window is pleasant and also stops at Ta' Pinu Basilica. Views of this site can be seen from the bus, so be sure to sit by the window (right side when going to the window) to catch a glimpse if you don't wish to stop.