Brussels has a good transportation system, and here you can use four (six) metrolines, trams and lots of buses. These should be able to get you from A to B, so if you just take a small look at our metro map and read the rest of our transportation information you will already have a good overview before you arrive.
The prices of the public transportation in Brussels are quite okay, but you can find more information about those at our public transportation page. If you arrive with flight to Belgium, you will probably arrive to Charleroi Airport or to Brussels Airport. Here you will find information about how to get to Brussels from the different airports.
Good luck and happy travelling in Brussels and Belgium!