To use Yahoo!7 Sports on your Mobile, you'll need a phone with WAP/GPRS access, which means your phone can access the Internet.
The easiest way to check if your mobile phone has WAP/GRPS is to look at your phone's menu or user manual. If they contain references to "web" "internet" or "browser", you should have WAP. You will also need to make sure that the settings for your connection are correct. If not, you will not be able to access this service. You may need to pay data charges incurred by your mobile provider to access this service.
If you're in doubt, give your mobile phone provider a call and they'll be able to tell you.