You got internet where? On your computer? Or the phone itself (using GPRS/Egde ?)
If latter, then you will have to configure a data network. Ask your operator for the data profile settings and create a new data profile with those settings. Then you can use that data profile in the phone's browser (or other browsers which you may have installed) and you can connect to the net.
Remember, it will charge you extra. Consult your tariff before you start downloading 50 mb files
