TV Converting: NTSC - PAL?

I bought a TV in England about 10 years and brought it over to Australia. We have another T.V and use the one from England for Playstation. But now we have decided that we want to be able to watch T.V on that too. So when connected up an ariel, on 1 or 2 channels we can barely see a picture as there are lines everywhere. But every other channel is blank and the channel names have stuff like - BBC and BBC2. There is also no sound on the 2 channels that have the slight picture. What problem is it and how can I fix it? Is it an NTSC to PAL problem? Let me know.